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A Study to Evaluate the Efficacy, Safety and Immunogenicity of a Vaccine Designed to Protect Against Infection With Shigella Sonnei in Healthy Adults

Efficacy, Safety and Immunogenicity of GVGH Shigella Sonnei Vaccine (1790GAHB) in a Human Challenge Study of Healthy Non-immune Adults

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03527173
Enrollment
71
Registered
2018-05-17
Start date
2018-08-29
Completion date
2019-11-11
Last updated
2020-07-28

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Dysentery, Bacillary

Keywords

Challenge, Efficacy, Shigellosis, Vaccination

Brief summary

The purpose of this study is to evaluate the efficacy, safety and immunogenicity of the GSK3536852A vaccine, which was designed to protect against shigellosis caused by Shigella sonnei (S. sonnei) and is using the new Generalized Modules for Membrane Antigens (GMMA) platform technology developed by GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH). The study vaccine could be the stepping stone for the development of a multivalent broadly protective Shigella vaccine for vaccination of impoverished communities where shigellosis is endemic. However, a standalone monovalent vaccine against S. sonnei could be used to protect travelers against diarrheal shigellosis, as the vast majority of travelers' shigellosis is caused by S. sonnei, and even to protect infants in endemic regions where shigellosis is primarily caused by S. sonnei. The GSK3536852A vaccine has been tested in two Phase I dose escalation studies in Europe to assess its safety and immunogenicity via three routes of administration: intramuscular (IM), intranasal (IN) and intradermal (ID). The results from the first study (dose escalation with IM vaccination) have shown that the vaccine has an acceptable safety profile and is well-tolerated up to a dose of 100 micrograms (µg). The results from the second study (dose escalation with ID, IN and IM vaccination) showed that GSK3536852A vaccine is well-tolerated also when administered by the ID and IN routes of vaccination. However, immunogenicity data have shown that GSK3536852A vaccine administered by the ID and IN routes is not as immunogenic as GSK3536852A vaccine administered by the IM route. Therefore, it has been decided to proceed with the clinical development program of this vaccine only using the IM vaccination route. In terms of dosage, the regimen tested in Phase I studies (three doses given one month apart) did not show any significant benefit from the third dose in terms of immunogenicity, therefore a two dose schedule was selected for next studies. A Phase IIa study, conducted in endemic regions of Africa (i.e., Kenya), has been completed and confirmed the acceptable safety profile and immunogenicity of GSK3536852A vaccine. Performing this vaccine-human challenge study may give the opportunity to establish evidence of clinical protection induced by the candidate S. sonnei vaccine (GSK3536852A vaccine) at an early development stage.

Detailed description

The original study protocol has been amended due to requests from the Food and Drug Administration (FDA), requests from the funder of the study, Bill & Melinda Gates Foundation (BMGF), to add an additional interim analysis for immunogenicity data that will accelerate the release of key results to help the planning of other studies, and to further align the protocol to other GSK studies and to the challenge model established at the Cincinnati Children's Hospital Medical Centre.

Interventions

BIOLOGICALS.sonnei vaccine

Subjects receiving 2 doses of the study vaccine by intramuscular route, 28 days apart (at Day 1 and Day 29).

DRUGPlacebo

Subjects receiving 2 doses of placebo by intramuscular route, 28 days apart (at Day 1 and Day 29).

BIOLOGICALS. sonnei 53G challenge strain

Subjects receiving the challenge dose of S. sonnei 53G strain, orally, at Day 57.

Sponsors

GlaxoSmithKline
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

Observer-blind The subject, the site and sponsor personnel involved in the clinical evaluation of the subjects are blinded while other study personnel may be aware of the treatment assignment.

Eligibility

Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes

Inclusion criteria

* Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol. * Written informed consent obtained from the subject prior to performing any study specific procedure. * Individuals who, after the nature of the study has been explained to them, have shown adequate comprehension of the study procedures and knowledge of study. * A male or female between, and including, 18 and 50 years of age at the time of the first vaccination. * Healthy subjects as established by medical history and clinical examination before entering into the study. * Seronegative for human immunodeficiency virus (HIV), hepatitis B and C. * Female subjects of non-childbearing potential may be enrolled in the study. * Female subjects of childbearing potential may be enrolled in the study, if the subject: * Has practiced adequate contraception for 30 days prior to vaccination, and * Has a negative pregnancy test on the day of vaccination, and * Has agreed to continue adequate contraception during the entire study period.

Exclusion criteria

* Received an investigational or non-registered medicinal product within 30 days prior to informed consent, or planned use during the study period. * Any behavioral or cognitive impairment or psychiatric disease that, in the opinion of the investigator, may interfere with the subject's ability to participate in the study. * History of any neurological disorders or seizures. * Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the subject due to participation in the study. * Human Leukocyte Antigen (HLA)-B27 positive test at screening and/or with history of reactive arthritis. * Clinical conditions representing a contraindication to intramuscular vaccination and blood draws. * Chronic administration of immunosuppressants or other immune-modifying drugs during the period starting six months prior to the first vaccine/placebo dose. For corticosteroids, this will mean prednisone ≥ 20 milligrams (mg)/day, or equivalent. Inhaled except for doses \> 800 µg/day and topical steroids are allowed. * Administration of long-acting immune-modifying drugs at any time during the study period. Subjects may be on chronic or as needed medications if, in the opinion of the site principal investigator or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity and do not indicate a worsening of medical diagnosis or condition. * Known bleeding diathesis or any condition that may be associated with a prolonged bleeding time. * Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product. * History of having participated in a previous Shigella challenge study. * Individuals who have a previously laboratory confirmed case of disease caused by S. sonnei or serology positive for local anti S. sonnei LPS IgG Screening-ELISA at screening. * History of any serious chronic or progressive disease according to judgment of the investigator. * History of any malignancy or lymphoproliferative disorder. * Known to be part of study personnel or being a close family member to the personnel conducting this study. * History of anaphylactic reaction or allergy to vaccine/placebo or challenge agent components or any other allergies deemed by the investigator to increase the risk of an AE if they were to participate in the study. * Known allergy to ciprofloxacin or the other antibiotics used for treatment as deemed by the investigator. * Individuals receiving a course of antibiotics within a week of the challenge will be ineligible to receive the challenge strain. * History of gastric acid hyper-secretory disorders as assessed and judged by the investigator or any other significant intestinal disorder. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination. * Family history of congenital or hereditary immunodeficiency. * History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine/placebo or challenge agent. * Acute disease and/or fever at the time of enrolment. * Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests. Chronic medical diagnoses or conditions should be stable for the last 60 days. This includes no change in chronic prescription medication, dose, or frequency as a result of deterioration of the chronic medical diagnosis or condition in the 60 days prior to enrolment. * A clinically significant sign or symptoms of acute illness, significant anomalies in vital signs. * Known to handle food as part of work related activities. * Hepatomegaly, right upper quadrant abdominal pain or tenderness. * Received immunoglobulins or any blood products within 180 days prior to informed consent or planned administration during the study period. * Pregnant or lactating female. * Female planning to become pregnant or planning to discontinue contraceptive precautions. * Females with history of stillbirth, neonatal loss, or previous infant with anomaly, except those who have had a planned termination of pregnancy, hysterectomy or bilateral tubal ligation. * History of chronic alcohol consumption and/or drug abuse. Chronic alcohol consumption is defined as: a prolonged period of frequent, heavy alcohol use; the inability to control drinking once it has begun; physical dependence manifested by withdrawal symptoms when the individual stops using alcohol; tolerance, or the need to use more and more alcohol to achieve the same effects; a variety of social and/or legal problems arising from alcohol use. * Known to have close household or professional contacts with people with immunosuppressive condition. * Documented HIV, hepatitis B and C positive subject. * Any condition which, in the opinion of the investigator, may pose an increased and unreasonable safety risk to the subject if they participated in the study. * Subjects with a baseline neutrophil count below 1800 cells per microliter (cells/µL) lower limit of normal range (LLN) OR with clinically significant abnormalities in other laboratory values, according to local reference ranges and investigator judgment. * Previous history of Benign Ethnic Neutropenia, or drug related Neutropenia. * Concomitant treatment with neutropenic agents.

Design outcomes

Primary

MeasureTime frameDescription
Percentage of Subjects With at Least One Episode of Shigellosis According to the Protocol Primary Case DefinitionStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Attack rate of shigellosis expressed as percentage of subjects with at least one episode of shigellosis after challenge, and 90% confidence interval (CI) (Clopper-Pearson method). Episodes of shigellosis fulfilling primary case definition: Shedding of S. sonnei 53G accompanied by moderate or severe diarrhea OR shedding with oral temperature greater than or equal to (≥) 38.5°C. Moderate diarrhea consists of 4 to 5 loose or watery (Grade \[G\]3 to 5) stools or 400 to 800 grams of G3 to 5 stools within 24 hours. Severe diarrhea consists of 6 or more loose or watery (G3 to 5) stools or \> 800 grams of G3 to 5 stools within 24 hours or required medical intervention. In case of severe diarrhea, medical intervention is defined as intravenous fluids administration or anticipation of antibiotic treatment before the 5th day after challenge. G3 = viscous opaque liquid or semi-liquid which assumes the shape of the bowl; G4 = watery opaque liquid; G5 = clear watery or mucoid liquid.

Secondary

MeasureTime frameDescription
Percentage of Subjects With at Least One Episode of ShigellosisStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Percentage of subjects with shigellosis fulfilling the following definition of shigellosis (with 90% confidence interval (CI) - Clopper-Pearson method): 1) severe diarrhea OR 2) moderate diarrhea AND oral temperature ≥ 38.0 °C OR ≥ 1 moderate constitutional/enteric symptom OR 3) dysentery \[\[≥ 2 loose stools with gross blood (hemoccult positive) in 24 hours\] AND \[≥ 1 reportable constitutional/enteric symptom\]\].
Percentage of Subjects With at Least One Episode of More Severe ShigellosisStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Percentage of subjects with more severe shigellosis fulfilling the following definition of more severe shigellosis (with 90% confidence interval (CI) - Clopper-Pearson method): 1) moderate OR severe diarrhea AND oral temperature ≥ 38.0 °C OR ≥ 1 severe constitutional/enteric symptom OR 2) dysentery \[\[≥ 2 loose stools with gross blood (hemoccult positive) in 24 hours\] AND \[oral temperature ≥ 38.0°C OR ≥ 1 severe constitutional/enteric symptom\]\].
Percentage of Subjects With Specific Disease SymptomsStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Percentage of subjects with 90% CI-Clopper-Pearson method was also measured for: shedding of S.sonnei strain 53G (defined as positivity of ≥1 stool sample by culture/quantitative Polymerase Chain Reaction/both); severe diarrhea; more severe diarrhea; dysentery; confirmed S.sonnei 53G shedding AND moderate or severe diarrhea OR dysentery OR presence of oral temperature ≥ 38.5°C OR presence of 1 or more severe intestinal symptoms (abdominal pain, cramping, nausea, vomiting, gas, and anorexia) abbreviated as shedding of S.sonnei 53G and \[…; disease not fulfilling the protocol primary case definition for shigellosis associated or not with mild to moderate symptoms including: ≥1 stool and no moderate or severe diarrhea evidence, abdominal pain, abdominal cramps, gas, anorexia, nausea, headache, myalgia, malaise, arthralgia, fever, vomiting and intravenous fluid administration. Any=any symptom regardless of intensity grade or relation to study vaccination and/or challenge administration.
Mean Number of Grade 3-5 Stools Per SubjectStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)The mean number of grade 3-5 stools (and standard deviation) were calculated per subject from challenge to discharge.
Weight of Grade 3-5 StoolsStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Mean and standard deviation (SD) of weights were expressed in grams. The following measures were calculated: mean and SD of the weight of grade 3-5 stools calculated on all subjects (Weight/all subjects), mean and SD of the weight of grade 3-5 stools calculated on subjects with at least one grade 3-5 stool (Weight/subj.with at least 1 grade 3-5 stool), Cumulative mean and SD weight of grade 3-5 stools per subjects, accumulated from challenge to discharge (Cumulative weight/all subjects).
Time (Days) From Challenge Administration to Onset of Shigellosis, According to the Primary Case DefinitionStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Median time to onset of shigellosis was to be estimated with Kaplan-Meier method among subjects who received the challenge agent. The day associated to the first shigellosis was the time of onset of shigellosis. Subjects who did not have shigellosis were censored at the time on the day of discharge. Median time (in days) to onset of shigellosis and 90% confidence interval (CI) could not be calculated in any of the groups because less than 50% of subjects experienced the event (shigellosis) during the observation period.
Number of Subjects With Any Solicited Local Adverse Events (AEs)During the 7-day period after each vaccination (vaccine/placebo administered at Day 1 and Day 29)Solicited local AEs include: pain, erythema and induration at injection site. Any = occurrence of local adverse event regardless of intensity grade. Any erythema or induration at injection site is any symptom with a surface diameter greater than 25 millimeters.
Number of Subjects With Any Solicited Systemic AEsDuring the 7-day period after each vaccination (vaccine/placebo administered at Day 1 and Day 29)Solicited systemic AEs include: arthralgia, chills, fatigue, headache, malaise, myalgia, fever (oral temperature ≥ 38.0°C). Any = occurrence of systemic adverse event regardless of intensity and relation to study vaccination.
Percentage of Subjects With at Least One Episode of Shigellosis According to Controlled Human Infection Model (CHIM) Working Group Case Definition for ShigellosisStarting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)Percentage of subjects with shigellosis fulfilling the CHIM expert working group case definition for shigellosis, and 90% confidence interval (CI) (Clopper-Pearson method). According to the working group, the participant must fulfil any of the three following possible endpoints to qualify as having reached the CHIM case definition for this objective: 1. Severe diarrhea defined as \[\[≥ 6 loose stools in 24 hours\] OR \[˃800 grams loose stools in 24 hours\]; 2. Moderate diarrhea defined as \[4-5 loose stools in 24 hours OR 400-800 grams loose stools in 24 hours\] AND \[oral temperature \[≥ 38.0°C OR \[≥ 1 moderate constitutional/enteric symptom OR \[≥ 2 episodes of vomiting in 24 hours\]; 3. Dysentery defined as \[\[≥ 2 loose stools with gross blood (hemoccult positive) in 24 hours\] AND \[oral temperature \[≥ 38.0°C OR \[≥ 1 moderate constitutional/enteric symptom OR \[≥ 2 episodes of vomiting in 24 hours\].
Number of Subjects With Any Unsolicited AEs During the 28-day Follow-up Period After ChallengeDuring the 28-day follow-up period after challenge (challenge administered at Day 57)An unsolicited AE covers any untoward medical occurrence in a clinical investigation subject temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product and reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms. Any was defined as the occurrence of any unsolicited AE regardless of intensity grade or relation to study vaccination and/or challenge agent administration.
Number of Subjects With Any Serious Adverse Events (SAEs) and Related SAEsFrom Day 1 up to study end at Day 237Serious adverse events (SAEs) assessed include medical occurrences that resulted in death, were life-threatening, required hospitalization or prolongation of hospitalization or resulted in disability/incapacity. Related SAEs = SAEs assessed by the investigator as related to the study vaccination and/or challenge agent administration.
Number of Subjects With Any Adverse Events of Special Interest (AESI) (i.e., Symptomatic Neutropenia)From Day 1 up to study end at Day 237AESI are predefined (serious or non-serious) AEs of scientific and medical concern specific to the product or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor can be appropriate, because such an event might warrant further investigation in order to characterize and understand it.
Number of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesAt Day 8, at Day 36 and at Day 237Among hematological parameters assessed are: Basophils, Eosinophils, Erythrocytes, Hematocrit, Hemoglobin, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets. Below = below the normal laboratory range defined for the specified laboratory parameter; Above = above the normal laboratory range defined for the specified laboratory parameter; Within = within the normal laboratory range defined for the specified laboratory parameter. Category naming has been defined as follows: Parameter, time point, range indicator at Baseline, range indicator at the specified time point: e.g.: Basophils, Day 8, Within, Within . Note: All subjects whose neutrophil value was below the threshold defined in the Protocol, at any time during the study, were re-tested until neutropenia resolution.
Anti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationAt Day 1 (pre-vaccination), at Day 8 (7 days after the first vaccination), at Day 29 (28 days after the first vaccination), at Day 36 (7 days after the second vaccination) and at Day 56 (27 days after the second vaccination)Anti-S. sonnei LPS IgG antibody concentrations are presented as geometric mean concentrations (GMCs), determined by Enzyme-linked immunosorbent assay (ELISA) and expressed in ELISA units per milliliter (EU/mL). Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination) timing.
Anti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeAt Day 56 (pre-challenge), at Day 64 (7 days after challenge) and at Day 85 (28 days after challenge)Anti-S. sonnei LPS IgG antibody concentrations are presented as GMCs, as determined by ELISA and expressed in EU/mL. Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination) timing.
Number of Subjects Achieving a Post-vaccination Anti-S. Sonnei LPS Concentration ≥ 268 EU/mLAt Day 29 (28 days after the first vaccination) and at Day 56 (27 days after the second vaccination)This antibody response cut-off was based on the results of the previous Phase I studies and estimated results of the median antibody titer after natural infection by S. sonnei. The threshold 121 EU/mL planned per protocol has been recalibrated to 268 EU/mL following an investigation of reliability of the ELISA assay. Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination) timing.
Number of Seroresponders for Anti-S. Sonnei LPSAt Day 29 (28 days after the first vaccination) and at Day 56 (27 days after the second vaccination)Seroresponse definition as reported in the protocol was assay specific and specifically related to assay, as run in Marburg Lab for the previous GVGH Shigella studies. This assay was further characterized and optimized before being used in GVGH for the current Phase 2b study. Since the assay used in current study is not comparable with the assay used in previous GVGH studies, the seroresponse definition is no longer appropriate (as it is valid only for Marburg assay). With the acknowledgment that seroresponse results are no longer meaningful, the study team choose to report the results for transparency. Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination timing.
Number of Subjects With Any Unsolicited AEs During the 28-day Post-vaccination PeriodDuring the 28-day period across doses (vaccine/placebo administered at Day 1 and Day 29)An unsolicited AE covers any untoward medical occurrence in a clinical investigation subject temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product and reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms. Any was defined as the occurrence of any unsolicited AE regardless of intensity grade or relation to study vaccination.

Countries

United States

Participant flow

Recruitment details

This study was conducted at one center in the United States of America (USA).

Pre-assignment details

All 71 subjects enrolled in the study, received a study vaccination and were included in the All Exposed Set.

Participants by arm

ArmCount
S. Sonnei Group
Male or female subjects between, and including, 18 and 50 years of age at the time of the first vaccination, received 2 doses of the S. sonnei study vaccine at Day 1 and Day 29 respectively, by intramuscular injection into the upper deltoid region of the non-dominant arm. At 28 days after the second dose (Day 57), subjects received the challenge dose of S. sonnei 53G strain, orally.
36
Placebo Group
Male or female subjects between, and including, 18 and 50 years of age at the time of the first vaccination, received 2 doses of the placebo at Day 1 and Day 29 respectively, by intramuscular injection into the upper deltoid region of the non-dominant arm. At 28 days after the second dose (Day 57), subjects received the challenge dose of S. sonnei 53G strain, orally.
35
Total71

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyCONSENT WITHDRAWAL NOT DUE TO ADV. EVENT15
Overall StudyELIGIBILITY CRITERIA NOT FULFILLED10
Overall StudyLost to Follow-up42
Overall StudyNOT WILLING TO PARTICIPATE THIS VISIT10

Baseline characteristics

CharacteristicS. Sonnei GroupPlacebo GroupTotal
Age, Continuous36.2 Years
STANDARD_DEVIATION 9.9
35.2 Years
STANDARD_DEVIATION 8.5
35.7 Years
STANDARD_DEVIATION 9.2
Race/Ethnicity, Customized
BLACK OR AFRICAN AMERICAN
24 Participants28 Participants52 Participants
Race/Ethnicity, Customized
OTHER - UNSPECIFIED
2 Participants1 Participants3 Participants
Race/Ethnicity, Customized
WHITE
10 Participants6 Participants16 Participants
Sex: Female, Male
Female
14 Participants17 Participants31 Participants
Sex: Female, Male
Male
22 Participants18 Participants40 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 360 / 35
other
Total, other adverse events
34 / 3633 / 35
serious
Total, serious adverse events
0 / 361 / 35

Outcome results

Primary

Percentage of Subjects With at Least One Episode of Shigellosis According to the Protocol Primary Case Definition

Attack rate of shigellosis expressed as percentage of subjects with at least one episode of shigellosis after challenge, and 90% confidence interval (CI) (Clopper-Pearson method). Episodes of shigellosis fulfilling primary case definition: Shedding of S. sonnei 53G accompanied by moderate or severe diarrhea OR shedding with oral temperature greater than or equal to (≥) 38.5°C. Moderate diarrhea consists of 4 to 5 loose or watery (Grade \[G\]3 to 5) stools or 400 to 800 grams of G3 to 5 stools within 24 hours. Severe diarrhea consists of 6 or more loose or watery (G3 to 5) stools or \> 800 grams of G3 to 5 stools within 24 hours or required medical intervention. In case of severe diarrhea, medical intervention is defined as intravenous fluids administration or anticipation of antibiotic treatment before the 5th day after challenge. G3 = viscous opaque liquid or semi-liquid which assumes the shape of the bowl; G4 = watery opaque liquid; G5 = clear watery or mucoid liquid.

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureValue (NUMBER)
S. Sonnei GroupPercentage of Subjects With at Least One Episode of Shigellosis According to the Protocol Primary Case Definition46.9 Percentage of subjects
Placebo GroupPercentage of Subjects With at Least One Episode of Shigellosis According to the Protocol Primary Case Definition42.9 Percentage of subjects
Comparison: To demonstrate the efficacy of two vaccinations with 25 µg of S. sonnei vaccine in healthy adults compared to placebo in preventing shigellosis, fulfilling the protocol primary case definition, after challenge with S. sonnei 53G strain. Vaccine efficacy (VE) rate was assessed as 1-Risk Ratio(RR) with RR = ratio of proportion of subjects with shigellosis in the vaccinated group on the proportion of subjects with shigellosis in the placebo group.p-value: 0.426690% CI: [-96.7, 33.7]1-sided Barnard Unconditional Exact Test
Secondary

Anti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second Vaccination

Anti-S. sonnei LPS IgG antibody concentrations are presented as geometric mean concentrations (GMCs), determined by Enzyme-linked immunosorbent assay (ELISA) and expressed in ELISA units per milliliter (EU/mL). Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination) timing.

Time frame: At Day 1 (pre-vaccination), at Day 8 (7 days after the first vaccination), at Day 29 (28 days after the first vaccination), at Day 36 (7 days after the second vaccination) and at Day 56 (27 days after the second vaccination)

Population: The analysis is performed on the Per protocol Set for immunogenicity, which includes all subjects who correctly received the study vaccine or placebo, have no protocol deviations leading to exclusion and provide post-vaccination immunogenicity data at the specified time points.

ArmMeasureGroupValue (GEOMETRIC_MEAN)
S. Sonnei GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 8229.18 EU/mL
S. Sonnei GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 36577.86 EU/mL
S. Sonnei GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 29523.21 EU/mL
S. Sonnei GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 56548.75 EU/mL
S. Sonnei GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 199.32 EU/mL
Placebo GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 56134.24 EU/mL
Placebo GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 1124.07 EU/mL
Placebo GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 8128.24 EU/mL
Placebo GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 29124.48 EU/mL
Placebo GroupAnti-S. Sonnei Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Antibody Concentrations at Pre-vaccination and After the First and Second VaccinationDay 36123.57 EU/mL
Secondary

Anti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After Challenge

Anti-S. sonnei LPS IgG antibody concentrations are presented as GMCs, as determined by ELISA and expressed in EU/mL. Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination) timing.

Time frame: At Day 56 (pre-challenge), at Day 64 (7 days after challenge) and at Day 85 (28 days after challenge)

Population: The analysis is performed on the Per protocol Set for immunogenicity, which includes all subjects who correctly received the study vaccine or placebo and challenge agent, have no protocol deviations leading to exclusion and provide post-vaccination immunogenicity data at the specified time points.

ArmMeasureGroupValue (GEOMETRIC_MEAN)
S. Sonnei GroupAnti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeDay 56529.4 EU/mL
S. Sonnei GroupAnti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeDay 64537.92 EU/mL
S. Sonnei GroupAnti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeDay 851039.07 EU/mL
Placebo GroupAnti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeDay 56150.59 EU/mL
Placebo GroupAnti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeDay 64216.11 EU/mL
Placebo GroupAnti-S. Sonnei LPS IgG Antibody Concentrations at Pre-challenge and After ChallengeDay 85810.97 EU/mL
Secondary

Mean Number of Grade 3-5 Stools Per Subject

The mean number of grade 3-5 stools (and standard deviation) were calculated per subject from challenge to discharge.

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureValue (MEAN)Dispersion
S. Sonnei GroupMean Number of Grade 3-5 Stools Per Subject28 grade 3-5 stoolsStandard Deviation 13
Placebo GroupMean Number of Grade 3-5 Stools Per Subject13.9 grade 3-5 stoolsStandard Deviation 6.6
Secondary

Number of Seroresponders for Anti-S. Sonnei LPS

Seroresponse definition as reported in the protocol was assay specific and specifically related to assay, as run in Marburg Lab for the previous GVGH Shigella studies. This assay was further characterized and optimized before being used in GVGH for the current Phase 2b study. Since the assay used in current study is not comparable with the assay used in previous GVGH studies, the seroresponse definition is no longer appropriate (as it is valid only for Marburg assay). With the acknowledgment that seroresponse results are no longer meaningful, the study team choose to report the results for transparency. Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination timing.

Time frame: At Day 29 (28 days after the first vaccination) and at Day 56 (27 days after the second vaccination)

Population: The analysis is performed on the Per protocol Set for immunogenicity, which includes all subjects who correctly received the study vaccine or placebo, have no protocol deviations leading to exclusion and provide post-vaccination immunogenicity data at the specified time points.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Seroresponders for Anti-S. Sonnei LPSDay 2932 Participants
S. Sonnei GroupNumber of Seroresponders for Anti-S. Sonnei LPSDay 5631 Participants
Placebo GroupNumber of Seroresponders for Anti-S. Sonnei LPSDay 290 Participants
Placebo GroupNumber of Seroresponders for Anti-S. Sonnei LPSDay 560 Participants
Secondary

Number of Subjects Achieving a Post-vaccination Anti-S. Sonnei LPS Concentration ≥ 268 EU/mL

This antibody response cut-off was based on the results of the previous Phase I studies and estimated results of the median antibody titer after natural infection by S. sonnei. The threshold 121 EU/mL planned per protocol has been recalibrated to 268 EU/mL following an investigation of reliability of the ELISA assay. Note: regarding the 28 days after second vaccination protocol timing, sample collection could have been performed either at Day 56 or at Day 57. For all the subjects, samples were collected at Day 56, and therefore, results are presented for Day 56 (27 days after the second vaccination) timing.

Time frame: At Day 29 (28 days after the first vaccination) and at Day 56 (27 days after the second vaccination)

Population: The analysis is performed on the Per protocol Set for immunogenicity, which includes all subjects who correctly received the study vaccine or placebo, have no protocol deviations leading to exclusion and provide post-vaccination immunogenicity data at the specified time points.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects Achieving a Post-vaccination Anti-S. Sonnei LPS Concentration ≥ 268 EU/mLDay 2924 Participants
S. Sonnei GroupNumber of Subjects Achieving a Post-vaccination Anti-S. Sonnei LPS Concentration ≥ 268 EU/mLDay 5624 Participants
Placebo GroupNumber of Subjects Achieving a Post-vaccination Anti-S. Sonnei LPS Concentration ≥ 268 EU/mLDay 297 Participants
Placebo GroupNumber of Subjects Achieving a Post-vaccination Anti-S. Sonnei LPS Concentration ≥ 268 EU/mLDay 567 Participants
Secondary

Number of Subjects With Any Adverse Events of Special Interest (AESI) (i.e., Symptomatic Neutropenia)

AESI are predefined (serious or non-serious) AEs of scientific and medical concern specific to the product or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor can be appropriate, because such an event might warrant further investigation in order to characterize and understand it.

Time frame: From Day 1 up to study end at Day 237

Population: The analysis is performed on the Overall Safety Set, which includes all enrolled subjects who received the study vaccine or placebo, and who are in the Solicited Safety Set and/or Unsolicited Safety Set.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Any Adverse Events of Special Interest (AESI) (i.e., Symptomatic Neutropenia)0 Participants
Placebo GroupNumber of Subjects With Any Adverse Events of Special Interest (AESI) (i.e., Symptomatic Neutropenia)0 Participants
Secondary

Number of Subjects With Any Serious Adverse Events (SAEs) and Related SAEs

Serious adverse events (SAEs) assessed include medical occurrences that resulted in death, were life-threatening, required hospitalization or prolongation of hospitalization or resulted in disability/incapacity. Related SAEs = SAEs assessed by the investigator as related to the study vaccination and/or challenge agent administration.

Time frame: From Day 1 up to study end at Day 237

Population: The analysis is performed on the Overall Safety Set, which includes all enrolled subjects who received the study vaccine or placebo, and who are in the Solicited Safety Set and/or Unsolicited Safety Set.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Any Serious Adverse Events (SAEs) and Related SAEsAny SAE(s)0 Participants
S. Sonnei GroupNumber of Subjects With Any Serious Adverse Events (SAEs) and Related SAEsRelated SAE(s)0 Participants
Placebo GroupNumber of Subjects With Any Serious Adverse Events (SAEs) and Related SAEsAny SAE(s)1 Participants
Placebo GroupNumber of Subjects With Any Serious Adverse Events (SAEs) and Related SAEsRelated SAE(s)0 Participants
Secondary

Number of Subjects With Any Solicited Local Adverse Events (AEs)

Solicited local AEs include: pain, erythema and induration at injection site. Any = occurrence of local adverse event regardless of intensity grade. Any erythema or induration at injection site is any symptom with a surface diameter greater than 25 millimeters.

Time frame: During the 7-day period after each vaccination (vaccine/placebo administered at Day 1 and Day 29)

Population: The analysis is performed on Solicited Safety Set, which includes all enrolled subjects who received the study vaccine or placebo, with valid data on solicited AEs and with the Subject Diary completed.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 1, Pain29 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 2, Pain24 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 1, Erythema0 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 2, Erythema0 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 1, Induration0 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 2, Induration0 Participants
Placebo GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 1, Induration1 Participants
Placebo GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 1, Pain12 Participants
Placebo GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 2, Erythema0 Participants
Placebo GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 2, Pain5 Participants
Placebo GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 2, Induration0 Participants
Placebo GroupNumber of Subjects With Any Solicited Local Adverse Events (AEs)Dose 1, Erythema0 Participants
Secondary

Number of Subjects With Any Solicited Systemic AEs

Solicited systemic AEs include: arthralgia, chills, fatigue, headache, malaise, myalgia, fever (oral temperature ≥ 38.0°C). Any = occurrence of systemic adverse event regardless of intensity and relation to study vaccination.

Time frame: During the 7-day period after each vaccination (vaccine/placebo administered at Day 1 and Day 29)

Population: The analysis is performed on Solicited Safety Set, which includes all enrolled subjects who received the study vaccine or placebo, with valid data on solicited AEs and with the Subject Diary completed.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Arthralgia6 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Arthralgia7 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Chills5 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Chills3 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Fatigue6 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Fatigue7 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Headache10 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Headache4 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Malaise8 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Malaise6 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Myalgia15 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Myalgia9 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Fever1 Participants
S. Sonnei GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Fever0 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Myalgia8 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Arthralgia3 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Headache4 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Arthralgia2 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Fever0 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Chills2 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Malaise4 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Chills1 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Myalgia7 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Fatigue8 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Malaise4 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Fatigue3 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 2, Fever0 Participants
Placebo GroupNumber of Subjects With Any Solicited Systemic AEsDose 1, Headache8 Participants
Secondary

Number of Subjects With Any Unsolicited AEs During the 28-day Follow-up Period After Challenge

An unsolicited AE covers any untoward medical occurrence in a clinical investigation subject temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product and reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms. Any was defined as the occurrence of any unsolicited AE regardless of intensity grade or relation to study vaccination and/or challenge agent administration.

Time frame: During the 28-day follow-up period after challenge (challenge administered at Day 57)

Population: The analysis is performed on the Unsolicited Safety Set, which includes all enrolled subjects who received the study vaccine or placebo, and the challenge agent administration, and with unsolicited AE data.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Any Unsolicited AEs During the 28-day Follow-up Period After Challenge20 Participants
Placebo GroupNumber of Subjects With Any Unsolicited AEs During the 28-day Follow-up Period After Challenge17 Participants
Secondary

Number of Subjects With Any Unsolicited AEs During the 28-day Post-vaccination Period

An unsolicited AE covers any untoward medical occurrence in a clinical investigation subject temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product and reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms. Any was defined as the occurrence of any unsolicited AE regardless of intensity grade or relation to study vaccination.

Time frame: During the 28-day period across doses (vaccine/placebo administered at Day 1 and Day 29)

Population: The analysis is performed on the Unsolicited Safety Set, which includes all enrolled subjects who received the study vaccine or placebo, with unsolicited AE data.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Any Unsolicited AEs During the 28-day Post-vaccination Period18 Participants
Placebo GroupNumber of Subjects With Any Unsolicited AEs During the 28-day Post-vaccination Period13 Participants
Secondary

Number of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory Ranges

Among hematological parameters assessed are: Basophils, Eosinophils, Erythrocytes, Hematocrit, Hemoglobin, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets. Below = below the normal laboratory range defined for the specified laboratory parameter; Above = above the normal laboratory range defined for the specified laboratory parameter; Within = within the normal laboratory range defined for the specified laboratory parameter. Category naming has been defined as follows: Parameter, time point, range indicator at Baseline, range indicator at the specified time point: e.g.: Basophils, Day 8, Within, Within . Note: All subjects whose neutrophil value was below the threshold defined in the Protocol, at any time during the study, were re-tested until neutropenia resolution.

Time frame: At Day 8, at Day 36 and at Day 237

Population: The analysis is performed on the Exposed Set, which includes all enrolled subjects who received the study vaccination and with laboratory data for the specified time points.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Within, Above4 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 237, Within, Within25 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Above, Within3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Below, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Above, Above4 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Within, Above2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Within, Within19 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Within, Above5 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 237, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Above, Within0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Within, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Above, Above5 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 237, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Within, Below1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Within, Within34 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Within, Above0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Below, Below4 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Below, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Within, Below1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Within, Within33 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Below, Within2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Within, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Within, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Within, Below0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 237, Above, Within3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Within, Within28 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Above, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Below, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 8, Within, Within36 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Within, Below0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 8, Within, Within35 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 36, Within, Within36 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Within, Within24 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Below, Below4 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Within, Below0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Within, Above0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Within, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Within, Below1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Unknown, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Within, Within24 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Above, Within2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Within, Below1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 8, Below, Below4 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Within, Within33 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 8, Within, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 8, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 8, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Below, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Above, Within2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Below, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 36, Unknown, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Within, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Below, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Within, Within29 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 36, Within, Within35 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 237, Below, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 237, Within, Below3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Below, Within2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 237, Within, Within23 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 237, Unknown, Within1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Below, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Within, Below1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Below, Within3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 237, Within, Within28 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Within, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Above, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Within, Within28 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Within, Within27 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Within, Within22 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Within, Above2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Below, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 36, Within, Within36 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Below, Within3 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Above, Within2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Within, Below1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Within, Above1 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Within, Within28 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Above, Above5 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Within, Above2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Within, Within32 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Within, Within25 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Below, Below2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 36, Within, Above0 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Below, Within2 Participants
S. Sonnei GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Within, Within31 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Below, Below3 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Below, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Within, Within27 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Within, Above0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 36, Above, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Below, Within3 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Within, Within28 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Within, Above2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Above, Within5 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 8, Above, Above0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Within, Within26 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Within, Above3 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Above, Within4 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 36, Above, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 237, Within, Within22 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 237, Within, Above2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesBasophils, Day 237, Above, Within4 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 8, Within, Within34 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 8, Within, Above0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 8, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 36, Within, Within32 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 36, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 36, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 237, Within, Within27 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesEosinophils, Day 237, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Within, Within31 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 8, Above, Within2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Within, Within30 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 36, Above, Within2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Within, Below0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Within, Within25 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesErythrocytes, Day 237, Above, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Below, Within0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Within, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Within, Within31 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 8, Above, Within2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Below, Within0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Within, Within29 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 36, Above, Within2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Within, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Within, Within21 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 237, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Below, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Within, Below0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Within, Within34 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 8, Within, Above0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 36, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 36, Within, Within33 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 237, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLymphocytes, Day 237, Within, Within27 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Within, Within25 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Within, Above5 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 8, Above, Above4 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Within, Within25 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Within, Above4 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 36, Above, Above4 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Within, Within13 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Within, Above10 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Above, Within2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesMonocytes, Day 237, Above, Above3 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Within, Below4 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Within, Within29 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 8, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Within, Within31 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Within, Above0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 36, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Within, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Within, Within25 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesNeutrophils, Day 237, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 8, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 8, Within, Within34 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 36, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 36, Within, Within33 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Below, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Within, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Within, Within25 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesPlatelets, Day 237, Within, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Within, Within24 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Above, Within1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHematocrit, Day 237, Above, Above1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 8, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 8, Within, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 8, Within, Within32 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Below, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Below, Within0 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Within, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 36, Within, Within32 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 237, Within, Below7 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesHemoglobin, Day 237, Within, Within21 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Below, Below2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Below, Within2 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Within, Below1 Participants
Placebo GroupNumber of Subjects With Change From Baseline in Hematological Laboratory Parameters With Respect to Normal Laboratory RangesLeukocytes, Day 8, Within, Within28 Participants
Secondary

Percentage of Subjects With at Least One Episode of More Severe Shigellosis

Percentage of subjects with more severe shigellosis fulfilling the following definition of more severe shigellosis (with 90% confidence interval (CI) - Clopper-Pearson method): 1) moderate OR severe diarrhea AND oral temperature ≥ 38.0 °C OR ≥ 1 severe constitutional/enteric symptom OR 2) dysentery \[\[≥ 2 loose stools with gross blood (hemoccult positive) in 24 hours\] AND \[oral temperature ≥ 38.0°C OR ≥ 1 severe constitutional/enteric symptom\]\].

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureValue (NUMBER)
S. Sonnei GroupPercentage of Subjects With at Least One Episode of More Severe Shigellosis15.6 Percentage of subjects
Placebo GroupPercentage of Subjects With at Least One Episode of More Severe Shigellosis14.3 Percentage of subjects
Secondary

Percentage of Subjects With at Least One Episode of Shigellosis

Percentage of subjects with shigellosis fulfilling the following definition of shigellosis (with 90% confidence interval (CI) - Clopper-Pearson method): 1) severe diarrhea OR 2) moderate diarrhea AND oral temperature ≥ 38.0 °C OR ≥ 1 moderate constitutional/enteric symptom OR 3) dysentery \[\[≥ 2 loose stools with gross blood (hemoccult positive) in 24 hours\] AND \[≥ 1 reportable constitutional/enteric symptom\]\].

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureValue (NUMBER)
S. Sonnei GroupPercentage of Subjects With at Least One Episode of Shigellosis46.9 Percentage of subjects
Placebo GroupPercentage of Subjects With at Least One Episode of Shigellosis35.7 Percentage of subjects
Secondary

Percentage of Subjects With at Least One Episode of Shigellosis According to Controlled Human Infection Model (CHIM) Working Group Case Definition for Shigellosis

Percentage of subjects with shigellosis fulfilling the CHIM expert working group case definition for shigellosis, and 90% confidence interval (CI) (Clopper-Pearson method). According to the working group, the participant must fulfil any of the three following possible endpoints to qualify as having reached the CHIM case definition for this objective: 1. Severe diarrhea defined as \[\[≥ 6 loose stools in 24 hours\] OR \[˃800 grams loose stools in 24 hours\]; 2. Moderate diarrhea defined as \[4-5 loose stools in 24 hours OR 400-800 grams loose stools in 24 hours\] AND \[oral temperature \[≥ 38.0°C OR \[≥ 1 moderate constitutional/enteric symptom OR \[≥ 2 episodes of vomiting in 24 hours\]; 3. Dysentery defined as \[\[≥ 2 loose stools with gross blood (hemoccult positive) in 24 hours\] AND \[oral temperature \[≥ 38.0°C OR \[≥ 1 moderate constitutional/enteric symptom OR \[≥ 2 episodes of vomiting in 24 hours\].

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureValue (NUMBER)
S. Sonnei GroupPercentage of Subjects With at Least One Episode of Shigellosis According to Controlled Human Infection Model (CHIM) Working Group Case Definition for Shigellosis46.9 Percentage of subjects
Placebo GroupPercentage of Subjects With at Least One Episode of Shigellosis According to Controlled Human Infection Model (CHIM) Working Group Case Definition for Shigellosis32.1 Percentage of subjects
Secondary

Percentage of Subjects With Specific Disease Symptoms

Percentage of subjects with 90% CI-Clopper-Pearson method was also measured for: shedding of S.sonnei strain 53G (defined as positivity of ≥1 stool sample by culture/quantitative Polymerase Chain Reaction/both); severe diarrhea; more severe diarrhea; dysentery; confirmed S.sonnei 53G shedding AND moderate or severe diarrhea OR dysentery OR presence of oral temperature ≥ 38.5°C OR presence of 1 or more severe intestinal symptoms (abdominal pain, cramping, nausea, vomiting, gas, and anorexia) abbreviated as shedding of S.sonnei 53G and \[…; disease not fulfilling the protocol primary case definition for shigellosis associated or not with mild to moderate symptoms including: ≥1 stool and no moderate or severe diarrhea evidence, abdominal pain, abdominal cramps, gas, anorexia, nausea, headache, myalgia, malaise, arthralgia, fever, vomiting and intravenous fluid administration. Any=any symptom regardless of intensity grade or relation to study vaccination and/or challenge administration.

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureGroupValue (NUMBER)
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Abdominal cramps53.1 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Myalgia34.4 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease Symptoms≥1 stool and no moderate/severe diarrhea evidence50.0 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Malaise46.9 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Gas40.6 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Arthralgia28.1 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsShedding of S. sonnei 53G and […46.9 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Fever9.4 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Anorexia43.8 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Vomiting21.9 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Abdominal pain50.0 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsIntravenous fluid administration0 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Nausea34.4 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsShedding of S. sonnei strain 53G96.9 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsDysentery34.4 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsSevere diarrhea40.6 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsAny Headache53.1 Percentage of subjects
S. Sonnei GroupPercentage of Subjects With Specific Disease SymptomsMore severe diarrhea34.4 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Headache60.7 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsDysentery28.6 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsShedding of S. sonnei 53G and […42.9 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease Symptoms≥1 stool and no moderate/severe diarrhea evidence60.7 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Abdominal pain46.4 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Abdominal cramps50.0 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Gas57.1 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Anorexia46.4 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Nausea32.1 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsMore severe diarrhea17.9 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Myalgia46.4 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Malaise57.1 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Arthralgia32.1 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Fever17.9 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsAny Vomiting7.1 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsIntravenous fluid administration0 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsShedding of S. sonnei strain 53G100 Percentage of subjects
Placebo GroupPercentage of Subjects With Specific Disease SymptomsSevere diarrhea25 Percentage of subjects
Secondary

Time (Days) From Challenge Administration to Onset of Shigellosis, According to the Primary Case Definition

Median time to onset of shigellosis was to be estimated with Kaplan-Meier method among subjects who received the challenge agent. The day associated to the first shigellosis was the time of onset of shigellosis. Subjects who did not have shigellosis were censored at the time on the day of discharge. Median time (in days) to onset of shigellosis and 90% confidence interval (CI) could not be calculated in any of the groups because less than 50% of subjects experienced the event (shigellosis) during the observation period.

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis was not performed because less than 50% of subjects experienced the event (shigellosis) during the observation period. Therefore, the Median time to onset of shigellosis and 90% confidence interval (CI) could not be calculated in any of the groups.

Secondary

Weight of Grade 3-5 Stools

Mean and standard deviation (SD) of weights were expressed in grams. The following measures were calculated: mean and SD of the weight of grade 3-5 stools calculated on all subjects (Weight/all subjects), mean and SD of the weight of grade 3-5 stools calculated on subjects with at least one grade 3-5 stool (Weight/subj.with at least 1 grade 3-5 stool), Cumulative mean and SD weight of grade 3-5 stools per subjects, accumulated from challenge to discharge (Cumulative weight/all subjects).

Time frame: Starting with the challenge visit (Day 57) and lasting up to the end of the inpatient stay (Day 64)

Population: The analysis is performed on the Per-protocol set (PPS) for efficacy, which includes all subjects who received the study vaccine or placebo according to protocol, were not excluded due to other reasons defined prior to unblinding or analysis and who received the challenge agent.

ArmMeasureGroupValue (MEAN)Dispersion
S. Sonnei GroupWeight of Grade 3-5 StoolsWeight/all subjects87.4 GramsStandard Deviation 68.3
S. Sonnei GroupWeight of Grade 3-5 StoolsWeight/subj. with at least 1 grade 3-5 stool127.2 GramsStandard Deviation 39.8
S. Sonnei GroupWeight of Grade 3-5 StoolsCumulative weight/all subjects1161.1 GramsStandard Deviation 1416.9
Placebo GroupWeight of Grade 3-5 StoolsWeight/subj. with at least 1 grade 3-5 stool116.3 GramsStandard Deviation 28.5
Placebo GroupWeight of Grade 3-5 StoolsCumulative weight/all subjects766.9 GramsStandard Deviation 884.9
Placebo GroupWeight of Grade 3-5 StoolsWeight/all subjects91.3 GramsStandard Deviation 54.7

Source: ClinicalTrials.gov · Data processed: Feb 21, 2026