Evaluating the Infectivity, Safety, and Immunogenicity of a Respiratory Syncytial Virus Vaccine (RSV 6120/∆NS2/1030s) in RSV-Seropositive Children and RSV-Seronegative Infants and Children

Phase I Placebo-Controlled Study of the Infectivity, Safety and Immunogenicity of a Single Dose of a Recombinant Live-Attenuated Respiratory Syncytial Virus Vaccine, RSV 6120/∆NS2/1030s, Lot RSV#012A, Delivered as Nose Drops to RSV-Seropositive Children 12 to 59 Months of Age and RSV-Seronegative Infants and Children 6 to 24 Months of Age

Status

Completed

Phases

Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT03387137

Enrollment

Registered

2017-12-29

Start date

2017-10-13

Completion date

2021-05-31

Last updated

2024-12-11

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

Conditions

RSV Infection

Brief summary

The purpose of this study is to evaluate the infectivity, safety, and immunogenicity of a single dose of a recombinant, live-attenuated respiratory syncytial virus (RSV) vaccine (RSV 6120/∆NS2/1030s) in RSV-seropositive children 12 to 59 months of age and RSV-seronegative infants and children 6 to 24 months of age.

Detailed description

This study will evaluate the infectivity, safety, and immunogenicity of a single dose of a recombinant, live-attenuated RSV vaccine (RSV 6120/∆NS2/1030s) in RSV-seropositive children 12 to 59 months of age and RSV-seronegative infants and children 6 to 24 months of age. The vaccine will be evaluated in a stepwise fashion beginning in RSV-seropositive children (Group 1), and then in RSV-seronegative infants and children (Group 2). In each group, participants will be randomly assigned to receive a single dose of RSV 6120/∆NS2/1030s vaccine or placebo at study entry (Day 0). Participants will be enrolled in the study between April 1 and October 31, outside of the RSV season. Group 1 (RSV-seropositive children) will be followed for 28 days. Group 2 (RSV-seronegative infants and children) will remain on study until they complete the post-RSV season visit. Group 2 participants may participate in an optional second season of RSV surveillance during November to March of the second year following enrollment. Study visits for all participants may include clinical assessments, blood collection, and nasal washes. Additionally, participants' parents or guardians will be contacted by study staff at various times during the study to monitor participants' health.

Interventions

BIOLOGICALRSV 6120/∆NS2/1030s

Delivered as nose drops

BIOLOGICALPlacebo

Delivered as nose drops

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

6 Months to 60 Months

Healthy volunteers

Yes

Inclusion criteria

for RSV-Seropositive Children: * Greater than or equal to 12 months of age and less than 60 months of age at the time of inoculation * Screening serum specimen for RSV neutralizing antibody is obtained within the calendar year of inoculation * Seropositive for RSV antibody, defined as serum RSV neutralizing antibody titer greater than or equal to 1:40 * Pre-inoculation serum sample for RSV neutralizing antibody testing is obtained no more than 56 days prior to inoculation * In good health based on review of the medical record, history, and physical examination at the time of inoculation * Received routine immunizations appropriate for age based on the Advisory Committee on Immunization Practices (ACIP) Recommended Immunization Schedule for Children and Adolescents Aged 18 Years or Younger * Growing normally for age as demonstrated on a standard growth chart and has a current height and weight above the 3rd percentile for age * Expected to be available for the duration of the study * Parent/guardian is willing and able to provide written informed consent

Exclusion criteria

for RSV-Seropositive Children: * Born at less than 34 weeks gestation * Maternal history of positive HIV test * Evidence of chronic disease * Known or suspected impairment of immune function * Bone marrow/solid organ transplant recipient * Major congenital malformations, including congenital cleft palate or cytogenetic abnormalities * Suspected or documented developmental disorder, delay, or other developmental problem * Cardiac abnormality requiring treatment * Lung disease or reactive airway disease * More than one episode of wheezing in the first year of life * Wheezing episode or received bronchodilator therapy within the past 12 months * Wheezing episode or received bronchodilator therapy after the age of 12 months * Previous receipt of supplemental oxygen therapy in a home setting * Previous receipt of an investigational RSV vaccine * Previous receipt or planned administration of anti-RSV drug (ribavirin) or RSV antibody product including RSV immune globulin (RSV Ig) or RSV monoclonal antibody (RSV mAb) * Previous receipt of immunoglobulin or any antibody products within the past 6 months * Previous receipt of any other blood products within the past 6 months * Previous anaphylactic reaction * Previous vaccine-associated adverse reaction that was Grade 3 or above * Known hypersensitivity to any vaccine component * Member of a household that contains an infant who is less than 12 months of age at the date of inoculation through the 10th day after inoculation * Member of a household that, at the date of inoculation through the 10th day after inoculation, contains an immunocompromised individual including but not limited to: * a person who is HIV-infected * a person who has received chemotherapy within the 12 months prior to enrollment * a person receiving immunosuppressant agents * a person living with a solid organ or bone marrow transplant * Will attend a daycare facility that does not separate children by age and contains an infant who is less than 12 months of age at the date of inoculation through the 10th day after inoculation * Receipt of any of the following prior to enrollment: * any inactivated vaccine or live-attenuated rotavirus vaccine within the 14 days prior, or * any live vaccine, other than rotavirus vaccine, within the 28 days prior, or * another investigational vaccine or investigational drug within 28 days prior, or * salicylate (aspirin) or salicylate-containing products within the past 28 days * Scheduled administration of any of the following after planned inoculation: * inactivated vaccine or live-attenuated rotavirus vaccine within the 14 days after, or * any live vaccine other than rotavirus in the 28 days after, or * another investigational vaccine or investigational drug in the 28 days after * Receipt of any of the following medications within 3 days of study enrollment: * systemic antibacterial, antiviral, antifungal, anti-parasitic, or antituberculous agents, whether for treatment or prophylaxis, or * intranasal medications, or * other prescription medications except the permitted concomitant medications listed below: * Permitted concomitant medications (prescription or non-prescription) include nutritional supplements, medications for gastroesophageal reflux, eye drops, and topical medications, including (but not limited to) cutaneous (topical) steroids, topical antibiotics, and topical antifungal agents. * Any of the following events at the time of enrollment: * fever (temporal or rectal temperature of greater than or equal to 100.4°F), or * upper respiratory signs or symptoms (rhinorrhea, cough, or pharyngitis) or * nasal congestion significant enough to interfere with successful inoculation, or * otitis media Inclusion Criteria for RSV-Seronegative Infants and Children: * Greater than or equal to 6 months of age and less than 25 months of age at the time of inoculation * Screening and pre-inoculation serum specimens for RSV-neutralizing antibody are obtained no more than 42 days prior to inoculation * Seronegative for RSV antibody, defined as serum RSV-neutralizing antibody titer less than 1:40 * In good health based on review of the medical record, history, and physical examination at the time of inoculation * Received routine immunizations appropriate for age based on the ACIP Recommended Immunization Schedule for Children and Adolescents Aged 18 Years or Younger * Growing normally for age as demonstrated on a standard growth chart, AND * If less than 1 year of age: has a current height and weight above the 5th percentile for age * If greater than or equal to 1 year of age: has a current height and weight above the 3rd percentile for age * Expected to be available for the duration of the study * Parent/guardian is willing and able to provide written informed consent

Design outcomes

Primary

Measure	Time frame	Description
RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)	Measured at Day 56	Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay. Serum antibody titers to RSV F glycoprotein were assessed by ELISA.
Peak Titer of Vaccine Virus Shed by Reverse Transcription Polymerase Chain Reaction (RSV-seronegative Subjects)	Measured at Days 0, 3, 5, 7, 10, 12, 14, 17 and 28	This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by reverse transcription polymerase chain reaction (RT-PCR). Only participants who met the definition of infection with vaccine virus were included.
Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seronegative Subjects)	Measured at Days 0, 3, 5, 7, 10, 12, 14, 17 and 28. Lat day positive is reported	As determined by a) culture and b) reverse transcription polymerase chain reaction (RT-PCR)
Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)	Measured at Day 0 and Day 28	Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay and an Enzyme-linked Immunosorbent Assay (ELISA). Antibody responses were defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre-inoculation and post-inoculation time points.
Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)	Measured at Day 0 and Day 56	Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay and an Enzyme-linked Immunosorbent Assay (ELISA). Antibody responses were defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre-inoculation and post-inoculation time points.
RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)	Measured at Day 28	Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay. Serum antibody titers to RSV F glycoprotein were assessed by ELISA.
Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Measured through Day 10	Solicited adverse events include fever; otitis media; upper respiratory illness (URI); lower respiratory illness (LRI) and cough (without LRI) as defined in Appendix IV of the protocol document. The number of participants who experienced solicited adverse events was presented. A participant was only counted once in each solicited AE category, and that is in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 21 and Table 22 in the protocol document.
Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Measured through Day 28	Solicited adverse events include fever; otitis media; upper respiratory illness (URI); lower respiratory illness (LRI) and cough (without LRI) as defined by Appendix IV in the protocol document . The number of participants who experienced solicited adverse events was presented. A participant was only counted once in each solicited AE category, and that is in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 21 and Table 22 in the protocol document.
Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seropositive Participants)	Measured through Day 10	Unsolicited adverse events were other events, not included in the solicited AEs. The number of participants who experienced unsolicited adverse events was presented.
Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seronegative Participants)	Measured through Day 28	Unsolicited adverse events were other events, not included in the solicited AEs. The number of participants who experienced unsolicited adverse events was presented.
Number of Participants With Serious Adverse Events (SAEs) (RSV-seropositive Participants)	Measured through Day 28	A Serious Adverse Event (SAE) is an AE, whether considered related to the study product or not, that: * Results in death during the period of protocol-defined surveillance; * Is life threatening: defined as an event in which the patient was at immediate risk of death at the time of the event; it does not refer to an event that hypothetically might have caused death were it more severe; * Requires inpatient hospitalization (or prolongation of existing hospitalization): defined as at least an overnight stay in the hospital or emergency ward for treatment that would have been inappropriate if administered in the outpatient setting; * Results in a persistent or significant disability/incapacity; * Is a congenital anomaly or birth defect, OR * Is an important medical event that may not be immediately life threatening or result in death or hospitalization but may jeopardize the patient or may require intervention to prevent one of the outcomes listed above.
Number of Participants With Serious Adverse Events (SAEs) (RSV-seronegative Participants)	Measured through Day 56	A Serious Adverse Event (SAE) is an AE, whether considered related to the study product or not, that: * Results in death during the period of protocol-defined surveillance; * Is life threatening: defined as an event in which the patient was at immediate risk of death at the time of the event; it does not refer to an event that hypothetically might have caused death were it more severe; * Requires inpatient hospitalization (or prolongation of existing hospitalization): defined as at least an overnight stay in the hospital or emergency ward for treatment that would have been inappropriate if administered in the outpatient setting; * Results in a persistent or significant disability/incapacity; * Is a congenital anomaly or birth defect, OR * Is an important medical event that may not be immediately life threatening or result in death or hospitalization but may jeopardize the patient or may require intervention to prevent one of the outcomes listed above.
Frequency of Infection With RSV Vaccine Virus (RSV-seropositive Subjects)	Measured through Day 28	As defined as 1) vaccine virus identified in a nasal wash (a binary outcome based on nasal washes done throughout the study period; Day 0 nasal wash will be counted as baseline) and/or 2) a greater than or equal to 4-fold rise in RSV neutralizing antibody titer and/or serum enzyme-linked immunosorbent assay (ELISA) titer to the RSV F protein from study entry to Study Day 28.
Frequency of Infection With RSV Vaccine Virus (RSV-seronegative Subjects)	Measured through Day 56	As defined as 1) vaccine virus identified in a nasal wash (a binary outcome based on nasal washes done throughout the study period; Day 0 nasal wash will be counted as baseline) and/or 2) a greater than or equal to 4-fold rise in RSV neutralizing antibody titer and/or serum enzyme-linked immunosorbent assay (ELISA) titer to the RSV F protein from study entry to Study Day 56.
Peak Titer of Vaccine Virus Shed Measured by Culture (RSV-seropositive Subjects)	Measured at Days 0, 3, 4, 5, 6, 7 and 10	This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by culture. Only participants who met the definition of infection with vaccine virus were included.
Peak Titer of Vaccine Virus Shed Measured by Reverse Transcription Polymerase Chain Reaction (RSV-seropositive Subjects)	Measured at Days 0, 3, 4, 5, 6, 7 and 10	This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by reverse transcription polymerase chain reaction (RT-PCR). Only participants who met the definition of infection with vaccine virus were included.
Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seropositive Subjects)	Measured at Days 0, 3, 4, 5, 6, 7 and 10. Last day positive is reported.	As determined by a) culture and b) reverse transcription polymerase chain reaction (RT-PCR)
Peak Titer of Vaccine Virus Shed by Culture (RSV-seronegative Subjects)	Measured at Days 0, 3, 5, 7, 10, 12, 14, 17 and 28	This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by culture. Only participants who met the definition of infection with vaccine virus were included.

Secondary

Measure	Time frame	Description
Frequency of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Measured through participants' last study visit, up to a total of 6 to 13 months after study entry, depending on when participants enroll in the study.	The number of participants who had RSV-associated, symptomatic, medically attended respiratory and febrile illness (MAARI) among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal washes collected during illness visits for MAARI events or a \> 4-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events.
Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Measured through participants' last study visit, up to a total of 6 to 13 months after study entry, depending on when participants enroll in the study	The number of participants who had RSV-associated, symptomatic, medically attended respiratory and febrile illness (MAARI) among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal washes collected during illness visits for MAARI events or a \> 4-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events. A participant was only counted once in each MAARI category, and that was in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 21 and Table 22 in the protocol document.Assessed by protocol-determined grading system
Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Measured pre- RSV Surveillance period (baseline) and post-RSV Surveillance period (4-6 months after the baseline)	Antibodies were assessed by RSV-neutralizing Antibody and Enzyme-linked Immunosorbent Assay (ELISA). A response was defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre- and post-RSV Surveillance time points.
Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance	Measured pre-RSV Surveillance period (baseline) and post-RSV Surveillance period (4-6 months after the baseline)	Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay and an Enzyme-linked Immunosorbent Assay (ELISA). Antibody responses were defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre-RSV surveillance and post-RSV surveillance time points among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal washes collected during illness visits for MAARI events or a \> 4-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events
Number of RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Measured through participants' last study visit, up to a total of 6 to 13 months after study entry, depending on when participants enrolled in the study.	As defined as 1) RSV identified in a nasal wash (a binary outcome based on nasal washes done throughout the RSV surveillance period; or 2) a greater than or equal to 4-fold rise in RSV neutralizing antibody titer or Serum IgG RSV F antibody titer from pre- to post-RSV Surveillance season

Countries

United States

Participant flow

Recruitment details

Participants were recruited from pediatric practices and clinics in the greater Baltimore/Washington area based on referral by the primary care provider or the provider's staff; and through mailing IRB-approved documents to children of local pediatric practices and clinics, and to households in local zip codes containing age-appropriate children between September 2017 and September 2019. The first participant was enrolled on 10/13/2017 and the last participant was enrolled on 9/27/2019.

Pre-assignment details

Of the 73 participants that were screened, 45 met eligibility criteria, parent agreed to enroll and were inoculated with study product.

Participants by arm

Arm	Count
Group 1: RSV 6120/∆NS2/1030s Vaccine RSV-seropositive children will receive a single dose of 10\^5.7 plaque-forming units (PFUs) of RSV 6120/∆NS2/1030s vaccine at study entry (Day 0). RSV 6120/∆NS2/1030s: Delivered as nose drops	10
Group 1: Placebo RSV-seropositive children will receive a single dose of placebo at study entry (Day 0). Placebo: Delivered as nose drops	5
Group 2: RSV 6120/∆NS2/1030s Vaccine RSV-seronegative infants and children will receive a single dose of 10\^5.0 PFUs of RSV 6120/∆NS2/1030s vaccine at study entry (Day 0). RSV 6120/∆NS2/1030s: Delivered as nose drops	20
Group 2: Placebo RSV-seronegative infants and children will receive a single dose of placebo at study entry (Day 0). Placebo: Delivered as nose drops	10
Total	45

Baseline characteristics

Characteristic	Group 1: RSV 6120/∆NS2/1030s Vaccine	Group 1: Placebo	Group 2: RSV 6120/∆NS2/1030s Vaccine	Group 2: Placebo	Total
Age, Customized < 1 year of age	0 Participants	0 Participants	7 Participants	5 Participants	12 Participants
Age, Customized 1 year of age	6 Participants	1 Participants	12 Participants	5 Participants	24 Participants
Age, Customized 2 years of age	1 Participants	2 Participants	1 Participants	0 Participants	4 Participants
Age, Customized 3 years of age	2 Participants	0 Participants	0 Participants	0 Participants	2 Participants
Age, Customized > 4 years of age	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Age, Customized 4 years of age	1 Participants	2 Participants	0 Participants	0 Participants	3 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants	0 Participants	2 Participants	0 Participants	2 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	10 Participants	5 Participants	18 Participants	10 Participants	43 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Asian	2 Participants	1 Participants	1 Participants	0 Participants	4 Participants
Race (NIH/OMB) Black or African American	1 Participants	0 Participants	1 Participants	0 Participants	2 Participants
Race (NIH/OMB) More than one race	1 Participants	3 Participants	2 Participants	1 Participants	7 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) White	6 Participants	1 Participants	16 Participants	9 Participants	32 Participants
Region of Enrollment United States	10 participants	5 participants	20 participants	10 participants	45 participants
Sex: Female, Male Female	6 Participants	4 Participants	11 Participants	3 Participants	24 Participants
Sex: Female, Male Male	4 Participants	1 Participants	9 Participants	7 Participants	21 Participants

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk	EG003 affected / at risk
deaths Total, all-cause mortality	0 / 10	0 / 5	0 / 20	0 / 10
other Total, other adverse events	6 / 10	2 / 5	20 / 20	9 / 10
serious Total, serious adverse events	0 / 10	0 / 5	0 / 20	0 / 10

Outcome results

Primary

Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seronegative Subjects)

As determined by a) culture and b) reverse transcription polymerase chain reaction (RT-PCR)

Time frame: Measured at Days 0, 3, 5, 7, 10, 12, 14, 17 and 28. Lat day positive is reported

Population: Only participants who met the definition of infection with vaccine virus were included.

Arm	Measure	Group	Value (MEAN)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seronegative Subjects)	Culture Positive	10.2 Days
Group 1: RSV 6120/∆NS2/1030s Vaccine	Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seronegative Subjects)	RT-PCR Positive	11.8 Days

Primary

Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seropositive Subjects)

As determined by a) culture and b) reverse transcription polymerase chain reaction (RT-PCR)

Time frame: Measured at Days 0, 3, 4, 5, 6, 7 and 10. Last day positive is reported.

Population: Only participants who met the definition of infection with vaccine virus were included.

Arm	Measure	Group	Value (MEAN)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seropositive Subjects)	Culture Positive	7.5 Days
Group 1: RSV 6120/∆NS2/1030s Vaccine	Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seropositive Subjects)	RT-PCR Positive	7.5 Days

Primary

Frequency of Infection With RSV Vaccine Virus (RSV-seronegative Subjects)

As defined as 1) vaccine virus identified in a nasal wash (a binary outcome based on nasal washes done throughout the study period; Day 0 nasal wash will be counted as baseline) and/or 2) a greater than or equal to 4-fold rise in RSV neutralizing antibody titer and/or serum enzyme-linked immunosorbent assay (ELISA) titer to the RSV F protein from study entry to Study Day 56.

Time frame: Measured through Day 56

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Frequency of Infection With RSV Vaccine Virus (RSV-seronegative Subjects)	20 Participants
Group 1: Placebo	Frequency of Infection With RSV Vaccine Virus (RSV-seronegative Subjects)	0 Participants

Primary

Frequency of Infection With RSV Vaccine Virus (RSV-seropositive Subjects)

Time frame: Measured through Day 28

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Frequency of Infection With RSV Vaccine Virus (RSV-seropositive Subjects)	2 Participants
Group 1: Placebo	Frequency of Infection With RSV Vaccine Virus (RSV-seropositive Subjects)	0 Participants

Primary

Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)

Time frame: Measured at Day 0 and Day 56

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Group	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)	Serum RSV Neutralizing Antibody Titers	18 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	17 Participants
Group 1: Placebo	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)	Serum RSV Neutralizing Antibody Titers	0 Participants
Group 1: Placebo	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	0 Participants

Primary

Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)

Time frame: Measured at Day 0 and Day 28

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Group	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)	Serum RSV Neutralizing Antibody Titers	0 Participants
Group 1: Placebo	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)	Serum RSV Neutralizing Antibody Titers	0 Participants
Group 1: Placebo	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	0 Participants

Primary

Number of Participants With Serious Adverse Events (SAEs) (RSV-seronegative Participants)

A Serious Adverse Event (SAE) is an AE, whether considered related to the study product or not, that: * Results in death during the period of protocol-defined surveillance; * Is life threatening: defined as an event in which the patient was at immediate risk of death at the time of the event; it does not refer to an event that hypothetically might have caused death were it more severe; * Requires inpatient hospitalization (or prolongation of existing hospitalization): defined as at least an overnight stay in the hospital or emergency ward for treatment that would have been inappropriate if administered in the outpatient setting; * Results in a persistent or significant disability/incapacity; * Is a congenital anomaly or birth defect, OR * Is an important medical event that may not be immediately life threatening or result in death or hospitalization but may jeopardize the patient or may require intervention to prevent one of the outcomes listed above.

Time frame: Measured through Day 56

Population: Study participants who received inoculation and were followed on study pst Day 0 were included.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Serious Adverse Events (SAEs) (RSV-seronegative Participants)	0 Participants
Group 1: Placebo	Number of Participants With Serious Adverse Events (SAEs) (RSV-seronegative Participants)	0 Participants

Primary

Number of Participants With Serious Adverse Events (SAEs) (RSV-seropositive Participants)

Time frame: Measured through Day 28

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Serious Adverse Events (SAEs) (RSV-seropositive Participants)	0 Participants
Group 1: Placebo	Number of Participants With Serious Adverse Events (SAEs) (RSV-seropositive Participants)	0 Participants

Primary

Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)

Solicited adverse events include fever; otitis media; upper respiratory illness (URI); lower respiratory illness (LRI) and cough (without LRI) as defined by Appendix IV in the protocol document . The number of participants who experienced solicited adverse events was presented. A participant was only counted once in each solicited AE category, and that is in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 21 and Table 22 in the protocol document.

Time frame: Measured through Day 28

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Group	Category	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Did not have this AE	19 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Did not have this AE	2 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Did not have this AE	19 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 1	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 1	18 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 2	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 2	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 2	4 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Did not have this AE	14 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 1	5 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 2	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 3	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Did not have this AE	14 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 2	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 2	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Did not have this AE	19 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Did not have this AE	8 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 1	1 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 2	1 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Fever	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Did not have this AE	6 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 1	4 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Upper Respiratory Illness (URI)	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Did not have this AE	10 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Did not have this AE	10 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	LRI in the absence of RSV shedding	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Did not have this AE	9 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 1	1 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Cough, without LRI	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Did not have this AE	10 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)	Otitis Media	Grade 2	0 Participants

Primary

Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)

Solicited adverse events include fever; otitis media; upper respiratory illness (URI); lower respiratory illness (LRI) and cough (without LRI) as defined in Appendix IV of the protocol document. The number of participants who experienced solicited adverse events was presented. A participant was only counted once in each solicited AE category, and that is in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 21 and Table 22 in the protocol document.

Time frame: Measured through Day 10

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Group	Category	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 1	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Did not have this AE	8 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 2	2 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Did not have this AE	6 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 1	4 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 2	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Did not have this AE	10 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 2	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Did not have this AE	9 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 2	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Did not have this AE	9 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 2	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Did not have this AE	10 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 2	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Did not have this AE	5 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Did not have this AE	5 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Did not have this AE	5 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Fever	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Did not have this AE	4 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 1	1 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 3	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Upper Respiratory Illness (URI)	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Did not have this AE	5 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	LRI in the absence of RSV shedding	Grade 4	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 1	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Otitis Media	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Lower Respiratory Illness (LRI) with RSV shedding	Grade 2	0 Participants
Group 1: Placebo	Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)	Cough without LRI	Did not have this AE	5 Participants

Primary

Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seronegative Participants)

Unsolicited adverse events were other events, not included in the solicited AEs. The number of participants who experienced unsolicited adverse events was presented.

Time frame: Measured through Day 28

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seronegative Participants)	9 Participants
Group 1: Placebo	Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seronegative Participants)	3 Participants

Primary

Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seropositive Participants)

Unsolicited adverse events were other events, not included in the solicited AEs. The number of participants who experienced unsolicited adverse events was presented.

Time frame: Measured through Day 10

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seropositive Participants)	3 Participants
Group 1: Placebo	Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seropositive Participants)	1 Participants

Primary

Peak Titer of Vaccine Virus Shed by Culture (RSV-seronegative Subjects)

This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by culture. Only participants who met the definition of infection with vaccine virus were included.

Time frame: Measured at Days 0, 3, 5, 7, 10, 12, 14, 17 and 28

Population: Only participants who met the definition of infection with vaccine virus were included.

Arm	Measure	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	Peak Titer of Vaccine Virus Shed by Culture (RSV-seronegative Subjects)	3.0 log 10 PFU/mL	Standard Deviation 0.8

Primary

Peak Titer of Vaccine Virus Shed by Reverse Transcription Polymerase Chain Reaction (RSV-seronegative Subjects)

This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by reverse transcription polymerase chain reaction (RT-PCR). Only participants who met the definition of infection with vaccine virus were included.

Time frame: Measured at Days 0, 3, 5, 7, 10, 12, 14, 17 and 28

Population: Only participants who met the definition of infection with vaccine virus were included.

Arm	Measure	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	Peak Titer of Vaccine Virus Shed by Reverse Transcription Polymerase Chain Reaction (RSV-seronegative Subjects)	4.5 log 10 copies/mL	Standard Deviation 0.8

Primary

Peak Titer of Vaccine Virus Shed Measured by Culture (RSV-seropositive Subjects)

Time frame: Measured at Days 0, 3, 4, 5, 6, 7 and 10

Population: Only participants who met the definition of infection with vaccine virus were included.

Arm	Measure	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	Peak Titer of Vaccine Virus Shed Measured by Culture (RSV-seropositive Subjects)	1.2 log 10 PFU/mL	Standard Deviation 0.5

Primary

Peak Titer of Vaccine Virus Shed Measured by Reverse Transcription Polymerase Chain Reaction (RSV-seropositive Subjects)

Time frame: Measured at Days 0, 3, 4, 5, 6, 7 and 10

Population: Only participants who met the definition of infection with vaccine virus were included.

Arm	Measure	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	Peak Titer of Vaccine Virus Shed Measured by Reverse Transcription Polymerase Chain Reaction (RSV-seropositive Subjects)	3.1 log 10 copies/mL	Standard Deviation 0.9

Primary

RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)

Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay. Serum antibody titers to RSV F glycoprotein were assessed by ELISA.

Time frame: Measured at Day 28

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Group	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	12.1 log 2 titers	Standard Deviation 1.5
Group 1: RSV 6120/∆NS2/1030s Vaccine	RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)	Serum RSV Neutralizing Antibody Titers	7.1 log 2 titers	Standard Deviation 1
Group 1: Placebo	RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)	Serum RSV Neutralizing Antibody Titers	7.2 log 2 titers	Standard Deviation 0.7
Group 1: Placebo	RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	12.9 log 2 titers	Standard Deviation 0.5

Primary

RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)

Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay. Serum antibody titers to RSV F glycoprotein were assessed by ELISA.

Time frame: Measured at Day 56

Population: Study participants who received inoculation and were followed on study past Day 0 were included.

Arm	Measure	Group	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)	Serum RSV Neutralizing Antibody Titers	6.5 log 2 titers	Standard Deviation 1.1
Group 1: RSV 6120/∆NS2/1030s Vaccine	RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	10.9 log 2 titers	Standard Deviation 1.7
Group 1: Placebo	RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)	Serum RSV Neutralizing Antibody Titers	2.6 log 2 titers	Standard Deviation 0.6
Group 1: Placebo	RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)	Serum IgG ELISA RSV F Antibody Interpolated Titers	6.0 log 2 titers	Standard Deviation 2

Secondary

Frequency of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season

Time frame: Measured through participants' last study visit, up to a total of 6 to 13 months after study entry, depending on when participants enroll in the study.

Population: Only participants who had RSV detected in nasal washes or had greater than or equal to 4 fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events were included. Four vaccinees and 2 placebo recipients were excluded due to SARS CoV-2 pandemic and no post-surveillance sample.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Frequency of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	4 Participants
Group 1: Placebo	Frequency of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	3 Participants

Secondary

Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance

Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay and an Enzyme-linked Immunosorbent Assay (ELISA). Antibody responses were defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre-RSV surveillance and post-RSV surveillance time points among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal washes collected during illness visits for MAARI events or a \> 4-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events

Time frame: Measured pre-RSV Surveillance period (baseline) and post-RSV Surveillance period (4-6 months after the baseline)

Population: Only participants who had RSV detected in nasal washes or had greater than or equal to 4 fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events were included.~Four vaccinees and 3 placebo recipients were excluded due to SARS CoV-2 pandemic and no post-surveillance sample.

Arm	Measure	Group	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance	Serum RSV Neutralizing Antibody	5 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance	Serum IgG ELISA RSV F Antibody Interpolated Titers	6 Participants
Group 1: Placebo	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance	Serum RSV Neutralizing Antibody	4 Participants
Group 1: Placebo	Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance	Serum IgG ELISA RSV F Antibody Interpolated Titers	4 Participants

Secondary

Number of RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season

As defined as 1) RSV identified in a nasal wash (a binary outcome based on nasal washes done throughout the RSV surveillance period; or 2) a greater than or equal to 4-fold rise in RSV neutralizing antibody titer or Serum IgG RSV F antibody titer from pre- to post-RSV Surveillance season

Time frame: Measured through participants' last study visit, up to a total of 6 to 13 months after study entry, depending on when participants enrolled in the study.

Population: Only participants who had RSV detected in nasal washes or had greater than or equal to 4 fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events were included.~Four vaccinees and 2 placebo recipients were excluded due to SARS CoV-2 pandemic and no post-surveillance sample.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Number of RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	6 Participants
Group 1: Placebo	Number of RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	5 Participants

Secondary

Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance

Antibodies were assessed by RSV-neutralizing Antibody and Enzyme-linked Immunosorbent Assay (ELISA). A response was defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre- and post-RSV Surveillance time points.

Time frame: Measured pre- RSV Surveillance period (baseline) and post-RSV Surveillance period (4-6 months after the baseline)

Population: Only participants who had RSV detected in nasal washes or had greater than or equal to 4 fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events were included.~Four vaccinees and 3 placebo recipients were excluded due to SARS CoV-2 pandemic and no post-surveillance sample.

Arm	Measure	Group	Value (MEAN)	Dispersion
Group 1: RSV 6120/∆NS2/1030s Vaccine	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Pre-RSV Surveillance Serum IgG ELISA RSV F Antibody Interpolated Titers	10.2 log 2 titers	Standard Deviation 1.9
Group 1: RSV 6120/∆NS2/1030s Vaccine	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Pre-RSV Surveillance Serum RSV Neutralizing Antibody	6.7 log 2 titers	Standard Deviation 1.4
Group 1: RSV 6120/∆NS2/1030s Vaccine	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Post-RSV Surveillance Serum RSV Neutralizing Antibody	10.7 log 2 titers	Standard Deviation 1.7
Group 1: RSV 6120/∆NS2/1030s Vaccine	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Post-RSV Surveillance Serum IgG ELISA RSV F Antibody Interpolated Titers	14.3 log 2 titers	Standard Deviation 1.4
Group 1: Placebo	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Post-RSV Surveillance Serum IgG ELISA RSV F Antibody Interpolated Titers	11.8 log 2 titers	Standard Deviation 1.3
Group 1: Placebo	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Pre-RSV Surveillance Serum IgG ELISA RSV F Antibody Interpolated Titers	5.4 log 2 titers	Standard Deviation 1.7
Group 1: Placebo	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Post-RSV Surveillance Serum RSV Neutralizing Antibody	8.1 log 2 titers	Standard Deviation 1
Group 1: Placebo	Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance	Pre-RSV Surveillance Serum RSV Neutralizing Antibody	3.0 log 2 titers	Standard Deviation 0.8

Secondary

Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season

The number of participants who had RSV-associated, symptomatic, medically attended respiratory and febrile illness (MAARI) among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal washes collected during illness visits for MAARI events or a \> 4-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events. A participant was only counted once in each MAARI category, and that was in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 21 and Table 22 in the protocol document.Assessed by protocol-determined grading system

Time frame: Measured through participants' last study visit, up to a total of 6 to 13 months after study entry, depending on when participants enroll in the study

Arm	Measure	Group	Category	Value (COUNT_OF_PARTICIPANTS)
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 3	2 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 2	4 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	No adverse event	3 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	No adverse event	3 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 2	3 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 2	1 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	No adverse event	4 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	No adverse event	4 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	No adverse event	2 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 2	2 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 3	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 1	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 4	0 Participants
Group 1: RSV 6120/∆NS2/1030s Vaccine	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 2	2 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 4	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	No adverse event	3 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 1	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 2	1 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 3	1 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Fever	Grade 4	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	No adverse event	1 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 1	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 2	4 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 3	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended URI	Grade 4	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	No adverse event	5 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 1	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 2	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 3	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended LRI	Grade 4	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	No adverse event	2 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 1	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 2	3 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 3	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Cough	Grade 4	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	No adverse event	4 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 1	0 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 2	1 Participants
Group 1: Placebo	Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season	Medically Attended Otitis Media	Grade 3	0 Participants

Source: ClinicalTrials.gov · Data processed: Feb 8, 2026

Evaluating the Infectivity, Safety, and Immunogenicity of a Respiratory Syncytial Virus Vaccine (RSV 6120/∆NS2/1030s) in RSV-Seropositive Children and RSV-Seronegative Infants and Children

Conditions

Brief summary

Detailed description

Related papers

Interventions

Sponsors

Study design

Eligibility

Inclusion criteria

Exclusion criteria

Design outcomes

Primary

Secondary

Countries

Participant flow

Recruitment details

Pre-assignment details

Participants by arm

Baseline characteristics

Adverse events

Outcome results

Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seronegative Subjects)

Duration of Vaccine Virus Shedding in Nasal Washes (RSV-seropositive Subjects)

Frequency of Infection With RSV Vaccine Virus (RSV-seronegative Subjects)

Frequency of Infection With RSV Vaccine Virus (RSV-seropositive Subjects)

Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein (RSV-seronegative Subjects)

Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein(RSV-seropositive Subjects)

Number of Participants With Serious Adverse Events (SAEs) (RSV-seronegative Participants)

Number of Participants With Serious Adverse Events (SAEs) (RSV-seropositive Participants)

Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seronegative Participants)

Number of Participants With Solicited Adverse Events (AEs) by Grade - (RSV-seropositive Participants)

Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seronegative Participants)

Number of Participants With Unsolicited Adverse Events (AEs) - (RSV-seropositive Participants)

Peak Titer of Vaccine Virus Shed by Culture (RSV-seronegative Subjects)

Peak Titer of Vaccine Virus Shed by Reverse Transcription Polymerase Chain Reaction (RSV-seronegative Subjects)

Peak Titer of Vaccine Virus Shed Measured by Culture (RSV-seropositive Subjects)

Peak Titer of Vaccine Virus Shed Measured by Reverse Transcription Polymerase Chain Reaction (RSV-seropositive Subjects)

RSV-neutralizing Serum Antibody Titer and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA)(RSV-seropositive Subjects)

RSV-neutralizing Serum Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) (RSV-seronegative Subjects)

Frequency of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season

Number of Participants With a Greater Than or Equal to 4-fold Rise in Serum RSV-neutralizing Antibody Titers and/or Serum Antibody Titers to RSV F Glycoprotein in RSV-seronegative Subjects (Group 2) Infected With wt RSV During the RSV Surveillance

Number of RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season

Serum RSV-neutralizing Antibody Titers and Immunoglobulin G (IgG) Serum Antibody Titers to RSV F Glycoprotein Enzyme-linked Immunosorbent Assay (ELISA) in Subjects (RSV-seronegative) Infected With wt RSV During the RSV Surveillance

Severity of Symptomatic, Medically Attended Respiratory and Febrile Illness in the RSV-seronegative (Group 2) Vaccine and Placebo Recipients Who Experience Natural Infection With wt RSV During the First RSV Season