A Trial to Evaluate the Efficacy and Safety of RSVpreF in Infants Born to Women Vaccinated During Pregnancy.

A PHASE 3, RANDOMIZED, DOUBLE-BLINDED, PLACEBO-CONTROLLED TRIAL TO EVALUATE THE EFFICACY AND SAFETY OF A RESPIRATORY SYNCYTIAL VIRUS (RSV) PREFUSION F SUBUNIT VACCINE IN INFANTS BORN TO WOMEN VACCINATED DURING PREGNANCY

Status

Completed

Phases

Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04424316

Enrollment

14727

Registered

2020-06-09

Start date

2020-06-17

Completion date

2023-10-27

Last updated

2025-02-11

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

Conditions

Respiratory Tract Infection

Keywords

Respiratory Tract infection, RSV, Vaccine, Maternal

Brief summary

This randomized, double-blinded, placebo-controlled Phase 3 study is designed to evaluate the efficacy and safety of maternal immunization with RSVpreF against medically attended lower respiratory tract illness (MA-LRTI) in infants.

Detailed description

This is a Phase 3, multicenter, randomized, double-blinded, placebo-controlled study to assess the efficacy, safety, and immunogenicity of RSVpreF or placebo (1:1 randomization) in infants born to healthy women vaccinated during pregnancy, as well as the safety and immunogenicity in the pregnant women. This will be a global study which will span multiple RSV seasons.

Interventions

BIOLOGICALRSVpreF

RSV vaccine (RSVpreF)

BIOLOGICALPlacebo

Placebo

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

This is a double-blinded, placebo-controlled study.

Eligibility

Sex/Gender

FEMALE

Age

0 Years to 49 Years

Healthy volunteers

Yes

Inclusion criteria

- Maternal Participants: * Healthy women ≤49 years of age who are between 24 0/7 and 36 0/7 weeks of gestation on the day of planned vaccination, with an uncomplicated, singleton pregnancy, who are at no known increased risk for complications. * Willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures. * Receiving prenatal standard of care based on country requirements. * Had a fetal anomaly ultrasound examination performed at ≥18 weeks of pregnancy with no significant fetal abnormalities observed. * Determined by medical history, physical examination, and clinical judgment to be appropriate for inclusion in the study. * Documented negative HIV antibody test, syphilis test, and hepatitis B virus (HBV) surface antigen test during this pregnancy and prior to randomization (Visit 1). * Intention to deliver at a hospital or birthing facility where study procedures can be obtained. * Expected to be available for the duration of the study and can be contacted by telephone during study participation. * Participant is willing to give informed consent for her infant to participate in the study. * Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent document (ICD) and in this protocol OR If the maternal participant is illiterate, a thumbprinted informed consent must be obtained, which must be signed and dated by an impartial witness who was present throughout the entire informed consent process confirming that the maternal participant has been informed of all pertinent aspects of the study. Inclusion Criteria -Infant Participants: * Evidence of a signed and dated ICD signed by the parent(s)/legal guardian(s) OR If the infant participant's maternal participant/parent(s)/legal guardian(s) is illiterate, a thumbprinted informed consent must have been obtained, which must have been signed and dated by an impartial witness who was present throughout the entire informed consent process confirming that the maternal participant/parent(s)/legal guardian(s) has been informed of all pertinent aspects of the study for herself (maternal participant) and her fetus/infant prior to taking part in the study. * Parent(s)/legal guardian(s) willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures.

Exclusion criteria

- Maternal Participants: * Prepregnancy body mass index (BMI) of \>40 kg/m2. If prepregnancy BMI is not available, the BMI at the time of the first obstetric visit during the current pregnancy may be used. * Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. * History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the investigational product or any related vaccine. * Current pregnancy resulting from in vitro fertilization. * Current pregnancy complications or abnormalities at the time of consent that will increase the risk associated with the participation in and completion of the study, including but not limited to the following: * Preeclampsia, eclampsia, or uncontrolled gestational hypertension. * Placental abnormality. * Polyhydramnios or oligohydramnios. * Significant bleeding or blood clotting disorder. * Endocrine disorders, including untreated hyperthyroidism or untreated hypothyroidism. This also includes disorders of glucose intolerance (eg, diabetes mellitus type 1 or 2) antedating pregnancy or occurring during pregnancy if uncontrolled at the time of consent. * Any signs of premature labor with the current pregnancy or having ongoing intervention (medical/surgical) in the current pregnancy to prevent preterm birth. * Prior pregnancy complications or abnormalities at the time of consent, based on the investigator's judgment, that will increase the risk associated with the participation in and completion of the study, including but not limited to the following: * Prior preterm delivery ≤34 weeks' gestation. * Prior stillbirth or neonatal death. * Previous infant with a known genetic disorder or significant congenital anomaly. * Major illness of the maternal participant or conditions of the fetus that, in the investigator's judgment, will substantially increase the risk associated with the maternal or infant participant's participation in, and completion of, the study or could preclude the evaluation of the maternal participant's response (includes positive serologic testing for regional endemic conditions assessed during routine maternal care, as per local standards of care and obstetric recommendations). * Congenital or acquired immunodeficiency disorder, or rheumatologic disorder or other illness requiring chronic treatment with known immunosuppressant medications, including monoclonal antibodies, within the year prior to enrollment. * Other acute or chronic medical or psychiatric condition including recent (within the past year) or active suicidal ideation or behavior or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study. * Participation in other studies involving investigational drug(s) within 28 days prior to consent and/or during study participation. * Receipt of monoclonal antibodies within the year prior to enrollment or the use of systemic corticosteroids for \>14 days within 28 days prior to study enrollment. Permitted treatments include the receipt of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibodies, prednisone doses of \<20 mg/day for ≤14 days and, inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids. * Current alcohol abuse or illicit drug use. Note: Marijuana use is not considered an exclusion criterion for the study when elicited in participant screening, though it may be considered illicit in some locales. * Receipt of blood or plasma products or immunoglobulin (Ig), from 60 days before investigational product administration, or planned receipt through delivery, with 1 exception, Rho(D) immune globulin (eg, RhoGAM), which can be given at any time. * Previous vaccination with any licensed or investigational RSV vaccine or planned. Note: Licensed COVID-19 vaccines or COVID-19 vaccines authorized for temporary or emergency use will not be prohibited during the course of this study. * Investigator site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, or Pfizer employees, including their family members, directly involved in the conduct of the study. * Participants who are breastfeeding at the time of enrollment.

Design outcomes

Primary

Measure	Time frame	Description
Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)	From vaccination on Day 1 up to 6 months after delivery (maximum up to 10 months)	An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event.
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	From Day 1 to Day 7 after vaccination	Local reactions included redness, swelling, and pain at injection site and were recorded in electronic diary (e-diary). Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit= 0.5 centimetre (cm). Redness and swelling were graded as mild (\>2.0 to 5.0 cm), moderate (\>5.0 to 10.0 cm), severe (\>10.0 cm) and grade 4 (necrosis or exfoliative dermatitis for redness and necrosis for swelling). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization for the severe pain at the injection site). Grade 4 reactions were classified by the investigator or medically qualified person.
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	From Day 1 to Day 7 after vaccination	Systemic events included: fever, fatigue, headache, nausea, muscle pain, joint pain, vomiting and diarrhea and were recorded by participants in an e-diary. Fever was defined as an oral temperature \>=38.0 degree Celsius \[C\]) and classified as mild (38.0 to 38.4), moderate (38.5 to 38.9), severe (39.0 to 40.0) and grade 4 (\>40.0 degree C). Headache, nausea, fatigue, muscle pain and joint pain were graded as mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily activity). Vomiting: mild (1-2 times in 24 hours \[H\]), moderate (\>2 times in 24 H), severe (required intravenous \[IV\] hydration). Diarrhea: mild (2-3 loose stools in 24 H), moderate (4-5 loose stools in 24 H), severe (\>=6 in 24 H). For all systemic events except fever, Grade 4= emergency room visit or hospitalization. Grade 4 events were classified by investigator or medically qualified person.
Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)	From vaccination on Day 1 up to 1 month after vaccination	An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were included in this outcome measure.
Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)	Within 90 days after birth	Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: infant with an MA-RTI visit with age related fast breathing (respiratory rate \[RR\] more than or equal to \[\>=\] 60 breaths per minute \[bpm\] for less than \[\<\] 2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or oxygen saturation (SpO2) \<95 percent (%) or chest wall indrawing and RSV positive test results by reverse transcription-polymerase chain reaction (RT-PCR) testing of midturbinate nasal swab samples.
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)	Within 120 days after birth	Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)	Within 150 days after birth	Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)	Within 180 days after birth	Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)	Within 90 days after birth	Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or intensive care unit (ICU) admission for more than (\>) 4 hours or failure to respond/unconscious.
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)	Within 120 days after birth	Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)	Within 150 days after birth	Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)	Within 180 days after birth	Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.
Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)	From birth to 24 months of age	AESI are a subset of targeted medical events based on review of known pharmacology, toxicology findings, possible class effects, published literature, and signals arising from safety data assessments, and on population under study. AESIs were based on targeted medical events associated with pregnant maternal participants and their infants prior to/during delivery and at birth. For infant participants the following were considered as protocol defined AESIs: Preterm birth (born at \<37 weeks gestation); birth weight 1001-2500 grams; developmental delay; positive viral (polymerase chain reaction \[PCR\] or antigen-based) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when not reported during MA-RTI visit, were reported as SARS-CoV-2 test positive. Extremely preterm birth (\<28 weeks) and extremely low birth weight (=\<1000 grams \[g\]) were reported as serious AESIs.
Percentage of Infant Participants With Neonatal Deaths (Safety)	Within 1 Month after birth	Neonatal death was defined as the death of a live-born infant that occurred within a month after birth.
Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)	At birth	Congenital malformations/ anomalies were defined as structural or functional anomalies that occurred during intrauterine life and could be identified prenatally, at birth or later in life.
Percentage of Infant Participants With Other Neonatal Events (Safety)	Within 1 Month after birth	Other Neonatal problem included dysmaturity, neonatal illness, hospitalization, drug therapies, and neonatal death.
Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	1 minute after birth	APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.
Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	5 minutes after birth	APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.
Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	10 minutes after birth	APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.
Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)	From birth to 1 month of age	An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)	From birth to 6 months of age	An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)	From birth to 12 months of age	An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)	From birth to 24 months of age	An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.

Secondary

Measure	Time frame	Description
Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	Within 90, 120, 150, 180 and 360 days after birth	MA-LRTI cases due to any cause was defined as an infant with a MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing.
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	Within 210, 240, 270 and 360 days after birth	Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	Within 90, 120, 150, 180 and 360 days after birth	Results are reported as confirmed by endpoint adjudication committee.

Countries

Argentina, Australia, Brazil, Canada, Chile, Denmark, Finland, Japan, Mexico, Netherlands, New Zealand, Philippines, South Africa, South Korea, Spain, Taiwan, The Gambia, United States

Participant flow

Pre-assignment details

A total of 14727 participants were enrolled (7420 maternal participants and 7307 infant participants) in the study.

Participants by arm

Arm	Count
Maternal Participants: RSVpreF Study-eligible pregnant women (maternal participants) were randomized to receive a single dose of 120 mcg RSVpreF, IM on Day 1 (day of vaccination). Participants were followed up to 6 months after delivery.	3,698
Maternal Participants: Placebo Maternal participants were randomized to receive placebo matching to RSVpreF as a single dose on Day 1 (day of vaccination). Participants were followed up to 6 months after delivery.	3,687
Infant Participants: RSVpreF Infant participants born to maternal participants vaccinated with a single dose of 120 mcg RSVpreF were included. Infant participants were all followed up for 12 months after birth, and for infants born to maternal participants during the first year of the study, they were followed up for 24 months after birth.	3,659
Infant Participants: Placebo Infant participants born to maternal participants who received placebo (matching RSVpreF without active vaccine) were included. Infant participants were all followed up for 12 months after birth, and for infants born to maternal participants during the first year of the study, they were followed up for 24 months after birth.	3,646
Total	14,690

Withdrawals & dropouts

Period	Reason	FG000	FG001	FG002	FG003
Overall Study	Adverse Event	0	1	0	0
Overall Study	Death	1	0	8	14
Overall Study	Lost to Follow-up	93	88	224	211
Overall Study	Mother vaccinated but unblinded during study	1	0	2	0
Overall Study	No longer met eligibility criteria	1	0	0	0
Overall Study	Other	15	11	34	45
Overall Study	Physician Decision	1	0	1	1
Overall Study	Protocol Violation	0	1	0	0
Overall Study	Randomized but not vaccinated	13	21	0	0
Overall Study	Withdrawal by parent/guardian	0	0	74	81
Overall Study	Withdrawal by Subject	71	77	0	0

Baseline characteristics

Characteristic	Maternal Participants: RSVpreF	Maternal Participants: Placebo	Infant Participants: RSVpreF	Infant Participants: Placebo	Total
Age, Categorical <=18 years	9 Participants	9 Participants	3659 Participants	3646 Participants	7323 Participants
Age, Categorical >=65 years	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Age, Categorical Between 18 and 65 years	3689 Participants	3678 Participants	0 Participants	0 Participants	7367 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1063 Participants	1086 Participants	1079 Participants	1081 Participants	4309 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	2605 Participants	2568 Participants	2529 Participants	2519 Participants	10221 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	30 Participants	33 Participants	51 Participants	46 Participants	160 Participants
Race (NIH/OMB) American Indian or Alaska Native	38 Participants	37 Participants	42 Participants	36 Participants	153 Participants
Race (NIH/OMB) Asian	456 Participants	464 Participants	446 Participants	456 Participants	1822 Participants
Race (NIH/OMB) Black or African American	720 Participants	725 Participants	706 Participants	706 Participants	2857 Participants
Race (NIH/OMB) More than one race	30 Participants	21 Participants	65 Participants	59 Participants	175 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	9 Participants	12 Participants	13 Participants	11 Participants	45 Participants
Race (NIH/OMB) Unknown or Not Reported	48 Participants	53 Participants	47 Participants	50 Participants	198 Participants
Race (NIH/OMB) White	2397 Participants	2375 Participants	2340 Participants	2328 Participants	9440 Participants
Sex: Female, Male Female	3698 Participants	3687 Participants	1794 Participants	1815 Participants	10994 Participants
Sex: Female, Male Male	0 Participants	0 Participants	1865 Participants	1831 Participants	3696 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	1 / 3,698	0 / 3,687	8 / 3,659	14 / 3,646
other Total, other adverse events	2,755 / 3,698	2,339 / 3,687	674 / 3,659	598 / 3,646
serious Total, serious adverse events	613 / 3,698	581 / 3,687	697 / 3,659	689 / 3,646

Outcome results

Primary

Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)

APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.

Time frame: 10 minutes after birth

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants. Here, Number of Participants Analyzed signifies participants evaluable for this outcome measure.

Arm	Measure	Category	Value (COUNT_OF_PARTICIPANTS)
Infant Participants: RSVpreF	Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	Score <4	0 Participants
Infant Participants: RSVpreF	Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	Score 4 to <7	6 Participants
Infant Participants: RSVpreF	Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	Score 7 to 10	993 Participants
Infant Participants: Placebo	Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	Score <4	0 Participants
Infant Participants: Placebo	Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	Score 4 to <7	4 Participants
Infant Participants: Placebo	Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)	Score 7 to 10	995 Participants

Primary

Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)

Time frame: 5 minutes after birth

Arm	Measure	Category	Value (COUNT_OF_PARTICIPANTS)
Infant Participants: RSVpreF	Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	Score <4	8 Participants
Infant Participants: RSVpreF	Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	Score 4 to <7	29 Participants
Infant Participants: RSVpreF	Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	Score 7 to 10	3581 Participants
Infant Participants: Placebo	Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	Score <4	5 Participants
Infant Participants: Placebo	Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	Score 4 to <7	27 Participants
Infant Participants: Placebo	Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)	Score 7 to 10	3570 Participants

Primary

Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)

Time frame: 1 minute after birth

Arm	Measure	Category	Value (COUNT_OF_PARTICIPANTS)
Infant Participants: RSVpreF	Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	Score <4	49 Participants
Infant Participants: RSVpreF	Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	Score 4 to <7	135 Participants
Infant Participants: RSVpreF	Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	Score 7 to 10	3441 Participants
Infant Participants: Placebo	Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	Score <4	44 Participants
Infant Participants: Placebo	Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	Score 4 to <7	124 Participants
Infant Participants: Placebo	Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)	Score 7 to 10	3438 Participants

Primary

Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)

Time frame: From birth to 1 month of age

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)	38.0 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)	35.4 Percentage of participants

Primary

Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)

AESI are a subset of targeted medical events based on review of known pharmacology, toxicology findings, possible class effects, published literature, and signals arising from safety data assessments, and on population under study. AESIs were based on targeted medical events associated with pregnant maternal participants and their infants prior to/during delivery and at birth. For infant participants the following were considered as protocol defined AESIs: Preterm birth (born at \<37 weeks gestation); birth weight 1001-2500 grams; developmental delay; positive viral (polymerase chain reaction \[PCR\] or antigen-based) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when not reported during MA-RTI visit, were reported as SARS-CoV-2 test positive. Extremely preterm birth (\<28 weeks) and extremely low birth weight (=\<1000 grams \[g\]) were reported as serious AESIs.

Time frame: From birth to 24 months of age

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)	11.9 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)	10.3 Percentage of participants

Primary

Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)

Congenital malformations/ anomalies were defined as structural or functional anomalies that occurred during intrauterine life and could be identified prenatally, at birth or later in life.

Time frame: At birth

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)	5.6 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)	6.7 Percentage of participants

Primary

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)

Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.

Time frame: Within 120 days after birth

Population: Evaluable efficacy - infant population included all infant participants who were born to the maternal participants who received the investigational product to which they were randomized (RSVpreF or placebo) at least 14 days prior to delivery; did not receive palivizumab or another monoclonal antibody targeting RSV; had no major protocol violations and did not have transfusions of more than 20 mL/kg of any blood products at \<180 days.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)	1.1 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)	2.5 % of participants with MA-LRTI cases

Comparison: Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. Vaccine efficacy was presented in percentage.95% CI: [33.2, 69.5]

Primary

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)

Time frame: Within 150 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)	1.5 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)	3.1 % of participants with MA-LRTI cases

Primary

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)

Time frame: Within 180 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)	1.9 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)	3.7 % of participants with MA-LRTI cases

Primary

Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)

Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: infant with an MA-RTI visit with age related fast breathing (respiratory rate \[RR\] more than or equal to \[\>=\] 60 breaths per minute \[bpm\] for less than \[\<\] 2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or oxygen saturation (SpO2) \<95 percent (%) or chest wall indrawing and RSV positive test results by reverse transcription-polymerase chain reaction (RT-PCR) testing of midturbinate nasal swab samples.

Time frame: Within 90 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)	0.7 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)	1.7 % of participants with MA-LRTI cases

Primary

Percentage of Infant Participants With Neonatal Deaths (Safety)

Neonatal death was defined as the death of a live-born infant that occurred within a month after birth.

Time frame: Within 1 Month after birth

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Neonatal Deaths (Safety)	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Neonatal Deaths (Safety)	0.1 Percentage of participants

Primary

Percentage of Infant Participants With Other Neonatal Events (Safety)

Other Neonatal problem included dysmaturity, neonatal illness, hospitalization, drug therapies, and neonatal death.

Time frame: Within 1 Month after birth

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Other Neonatal Events (Safety)	6.2 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Other Neonatal Events (Safety)	5.5 Percentage of participants

Primary

Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)

An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.

Time frame: From birth to 12 months of age

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)	SAE	17.3 Percentage of participants
Infant Participants: RSVpreF	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)	NDCMC	2.1 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)	SAE	17.2 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)	NDCMC	2.3 Percentage of participants

Primary

Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)

Time frame: From birth to 24 months of age

Population: Infant safety population included all infant participants who were born to vaccinated maternal participants.

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)	SAE	19.0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)	NDCMC	3.9 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)	SAE	18.9 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)	NDCMC	4.5 Percentage of participants

Primary

Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)

An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.

Time frame: From birth to 6 months of age

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)	SAE	16.7 Percentage of participants
Infant Participants: RSVpreF	Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)	NDCMC	1.3 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)	SAE	16.4 Percentage of participants
Infant Participants: Placebo	Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)	NDCMC	1.6 Percentage of participants

Primary

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)

Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.

Time frame: Within 120 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)	0.4 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)	1.4 % of participants with MA-LRTI cases

Primary

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)

Time frame: Within 150 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)	0.5 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)	1.7 % of participants with MA-LRTI cases

Primary

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)

Time frame: Within 180 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)	0.6 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)	2.0 % of participants with MA-LRTI cases

Primary

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)

Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or intensive care unit (ICU) admission for more than (\>) 4 hours or failure to respond/unconscious.

Time frame: Within 90 days after birth

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)	0.2 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)	1.0 % of participants with MA-LRTI cases

Primary

Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)

An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were included in this outcome measure.

Time frame: From vaccination on Day 1 up to 1 month after vaccination

Population: Maternal safety population included all randomized maternal participants who received investigational product.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)	14.0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)	13.2 Percentage of participants

Primary

Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)

Local reactions included redness, swelling, and pain at injection site and were recorded in electronic diary (e-diary). Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit= 0.5 centimetre (cm). Redness and swelling were graded as mild (\>2.0 to 5.0 cm), moderate (\>5.0 to 10.0 cm), severe (\>10.0 cm) and grade 4 (necrosis or exfoliative dermatitis for redness and necrosis for swelling). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization for the severe pain at the injection site). Grade 4 reactions were classified by the investigator or medically qualified person.

Time frame: From Day 1 to Day 7 after vaccination

Population: Maternal safety population included all randomized maternal participants who received investigational product. Here, Number of Participants Analyzed signifies participants evaluable for this outcome measure.

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Severe	0.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Mild	5.0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Any	6.2 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Any	40.7 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Severe	0.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Mild	36.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Mild	4.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Moderate	4.5 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Moderate	2.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Severe	0.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Moderate	2.0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Any	7.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Any	0.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Mild	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Moderate	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Severe	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Redness: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Any	0.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Mild	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Moderate	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Severe	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Swelling: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Any	10.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Mild	9.3 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Moderate	0.9 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)	Pain at injection site: Severe	0 Percentage of participants

Primary

Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)

Systemic events included: fever, fatigue, headache, nausea, muscle pain, joint pain, vomiting and diarrhea and were recorded by participants in an e-diary. Fever was defined as an oral temperature \>=38.0 degree Celsius \[C\]) and classified as mild (38.0 to 38.4), moderate (38.5 to 38.9), severe (39.0 to 40.0) and grade 4 (\>40.0 degree C). Headache, nausea, fatigue, muscle pain and joint pain were graded as mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily activity). Vomiting: mild (1-2 times in 24 hours \[H\]), moderate (\>2 times in 24 H), severe (required intravenous \[IV\] hydration). Diarrhea: mild (2-3 loose stools in 24 H), moderate (4-5 loose stools in 24 H), severe (\>=6 in 24 H). For all systemic events except fever, Grade 4= emergency room visit or hospitalization. Grade 4 events were classified by investigator or medically qualified person.

Time frame: From Day 1 to Day 7 after vaccination

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Any	31.0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: 38.0 to 38.4 degree C	1.7 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: 38.5 to 38.9 degree C	0.8 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: 39.0 to 40.0 degree C	0.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: >40.0 degree C	0.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Any	46.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Mild	23.5 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Moderate	21.3 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Severe	1.3 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: >=38.0 degree C	2.6 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Mild	20.2 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Moderate	10.4 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Severe	0.4 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Any	20.0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Mild	14.4 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Moderate	5.4 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Severe	0.2 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Any	26.6 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Mild	17.6 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Moderate	8.6 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Severe	0.4 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Any	11.6 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Mild	6.5 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Moderate	4.9 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Severe	0.2 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Any	7.9 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Mild	6.4 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Moderate	1.3 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Severe	0.2 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Grade 4	0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Any	11.3 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Mild	9.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Moderate	2.0 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Severe	0.1 Percentage of participants
Infant Participants: RSVpreF	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Moderate	1.9 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: >=38.0 degree C	2.9 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Any	17.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: 38.0 to 38.4 degree C	1.5 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Any	7.0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: 38.5 to 38.9 degree C	1.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Mild	10.0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: 39.0 to 40.0 degree C	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Any	11.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fever: >40.0 degree C	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Moderate	6.8 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Any	43.8 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Mild	5.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Mild	22.7 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Severe	0.3 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Moderate	19.6 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Severe	1.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Muscle pain: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Fatigue: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Moderate	1.5 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Any	27.6 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Any	10.5 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Mild	17.9 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Mild	9.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Moderate	9.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Mild	6.0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Severe	0.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Severe	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Headache: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Moderate	4.4 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Any	19.3 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Diarrhea: Severe	0.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Mild	13.9 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Severe	0.1 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Moderate	5.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Vomiting: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Severe	0.2 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Joint pain: Grade 4	0 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)	Nausea: Grade 4	0 Percentage of participants

Primary

Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)

An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event.

Time frame: From vaccination on Day 1 up to 6 months after delivery (maximum up to 10 months)

Population: Maternal safety population included all randomized maternal participants who received investigational product.

Arm	Measure	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)	16.6 Percentage of participants
Infant Participants: Placebo	Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)	15.8 Percentage of participants

Secondary

Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)

Results are reported as confirmed by endpoint adjudication committee.

Time frame: Within 90, 120, 150, 180 and 360 days after birth

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	120 days after birth	0.4 %participants with hospitalization cases
Infant Participants: RSVpreF	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	180 days after birth	0.6 %participants with hospitalization cases
Infant Participants: RSVpreF	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	150 days after birth	0.5 %participants with hospitalization cases
Infant Participants: RSVpreF	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	360 days after birth	1.4 %participants with hospitalization cases
Infant Participants: RSVpreF	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	90 days after birth	0.3 %participants with hospitalization cases
Infant Participants: Placebo	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	360 days after birth	1.9 %participants with hospitalization cases
Infant Participants: Placebo	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	90 days after birth	0.9 %participants with hospitalization cases
Infant Participants: Placebo	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	120 days after birth	1.1 %participants with hospitalization cases
Infant Participants: Placebo	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	150 days after birth	1.2 %participants with hospitalization cases
Infant Participants: Placebo	Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	180 days after birth	1.3 %participants with hospitalization cases

Comparison: Vaccine efficacy within 180 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. Vaccine efficacy was presented in percentage.95% CI: [23.8, 74.6]

Comparison: Vaccine efficacy within 360 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. Vaccine efficacy was presented in percentage.95% CI: [-11.1, 48.6]

Secondary

Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)

MA-LRTI cases due to any cause was defined as an infant with a MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing.

Time frame: Within 90, 120, 150, 180 and 360 days after birth

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	120 days after birth	8.1 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	180 days after birth	12.4 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	150 days after birth	10.3 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	360 days after birth	17.5 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	90 days after birth	5.6 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	360 days after birth	18.4 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	90 days after birth	6.2 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	120 days after birth	8.8 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	150 days after birth	11.3 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)	180 days after birth	13.0 % of participants with MA-LRTI cases

Comparison: Vaccine efficacy within 90 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [-10.1, 25.7]

Comparison: Vaccine efficacy within 120 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [-9.8, 20.7]

Comparison: Vaccine efficacy within 150 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [-6.5, 20.1]

Comparison: Vaccine efficacy within 180 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [-9.5, 16]

Comparison: Vaccine efficacy within 360 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [-6.6, 14.6]

Secondary

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)

Time frame: Within 210, 240, 270 and 360 days after birth

Arm	Measure	Group	Value (NUMBER)
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	240 days after birth	2.5 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	270 days after birth	2.8 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	360 days after birth	3.4 % of participants with MA-LRTI cases
Infant Participants: RSVpreF	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	210 days after birth	2.3 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	210 days after birth	4.0 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	240 days after birth	4.2 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	360 days after birth	5.1 % of participants with MA-LRTI cases
Infant Participants: Placebo	Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)	270 days after birth	4.4 % of participants with MA-LRTI cases

Comparison: Vaccine efficacy at 210 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [25.6, 57.7]

Comparison: Vaccine efficacy at 240 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [21.3, 54.1]

Comparison: Vaccine efficacy at 270 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [16.1, 49.9]

Comparison: Vaccine efficacy at 360 days after birth. Vaccine efficacy was calculated as 1-(P/\[1-P\]), where P is the number of cases in the RSVpreF group divided by the total number of cases. The confidence interval was adjusted using Bonferroni procedure and accounting for the primary endpoints results. Vaccine efficacy was presented in percentage.95% CI: [15.2, 47.1]

Source: ClinicalTrials.gov · Data processed: Feb 18, 2026

A Trial to Evaluate the Efficacy and Safety of RSVpreF in Infants Born to Women Vaccinated During Pregnancy.

Conditions

Keywords

Brief summary

Detailed description

Related papers

Interventions

Sponsors

Study design

Masking description

Eligibility

Inclusion criteria

Exclusion criteria

Design outcomes

Primary

Secondary

Countries

Participant flow

Pre-assignment details

Participants by arm

Withdrawals & dropouts

Baseline characteristics

Adverse events

Outcome results

Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)

Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)

Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)

Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)

Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)

Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)

Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)

Percentage of Infant Participants With Neonatal Deaths (Safety)

Percentage of Infant Participants With Other Neonatal Events (Safety)

Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)

Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)

Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)

Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)

Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)

Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)

Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)

Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)

Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)

Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)

Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)