Trial Outcomes & Findings for A Trial to Evaluate the Efficacy and Safety of RSVpreF in Infants Born to Women Vaccinated During Pregnancy. (NCT NCT04424316)

Last Updated: 2025-02-11

Results Overview

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.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

14727 participants

Primary outcome timeframe

Within 90 days after birth

Results posted on

2025-02-11

Participant Flow

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

Participant milestones

Participant milestones
Measure	Maternal Participants: RSVpreF Study-eligible pregnant women (maternal participants) were randomized to receive a single dose of 120 micrograms (mcg) respiratory syncytial virus stabilized prefusion F subunit vaccine (RSVpreF), intramuscularly (IM) on Day 1 (day of vaccination). Participants were followed up to 6 months after delivery.	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.	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.	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.
Overall Study STARTED	3712	3708	3661	3646
Overall Study Safety Population	3698	3687	3659	3646
Overall Study COMPLETED	3516	3509	3318	3294
Overall Study NOT COMPLETED	196	199	343	352

Reasons for withdrawal

Reasons for withdrawal
Measure	Maternal Participants: RSVpreF Study-eligible pregnant women (maternal participants) were randomized to receive a single dose of 120 micrograms (mcg) respiratory syncytial virus stabilized prefusion F subunit vaccine (RSVpreF), intramuscularly (IM) on Day 1 (day of vaccination). Participants were followed up to 6 months after delivery.	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.	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.	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.
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 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 Withdrawal by Subject	71	77	0	0
Overall Study Withdrawal by parent/guardian	0	0	74	81
Overall Study Randomized but not vaccinated	13	21	0	0
Overall Study Mother vaccinated but unblinded during study	1	0	2	0

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Maternal Participants: RSVpreF n=3698 Participants 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.	Maternal Participants: Placebo n=3687 Participants 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.	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.	Total n=14690 Participants Total of all reporting groups
Age, Categorical <=18 years	9 Participants n=5 Participants	9 Participants n=7 Participants	3659 Participants n=5 Participants	3646 Participants n=4 Participants	7323 Participants n=21 Participants
Age, Categorical Between 18 and 65 years	3689 Participants n=5 Participants	3678 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	7367 Participants n=21 Participants
Age, Categorical >=65 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Sex: Female, Male Female	3698 Participants n=5 Participants	3687 Participants n=7 Participants	1794 Participants n=5 Participants	1815 Participants n=4 Participants	10994 Participants n=21 Participants
Sex: Female, Male Male	0 Participants n=5 Participants	0 Participants n=7 Participants	1865 Participants n=5 Participants	1831 Participants n=4 Participants	3696 Participants n=21 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1063 Participants n=5 Participants	1086 Participants n=7 Participants	1079 Participants n=5 Participants	1081 Participants n=4 Participants	4309 Participants n=21 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	2605 Participants n=5 Participants	2568 Participants n=7 Participants	2529 Participants n=5 Participants	2519 Participants n=4 Participants	10221 Participants n=21 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	30 Participants n=5 Participants	33 Participants n=7 Participants	51 Participants n=5 Participants	46 Participants n=4 Participants	160 Participants n=21 Participants
Race (NIH/OMB) American Indian or Alaska Native	38 Participants n=5 Participants	37 Participants n=7 Participants	42 Participants n=5 Participants	36 Participants n=4 Participants	153 Participants n=21 Participants
Race (NIH/OMB) Asian	456 Participants n=5 Participants	464 Participants n=7 Participants	446 Participants n=5 Participants	456 Participants n=4 Participants	1822 Participants n=21 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	9 Participants n=5 Participants	12 Participants n=7 Participants	13 Participants n=5 Participants	11 Participants n=4 Participants	45 Participants n=21 Participants
Race (NIH/OMB) Black or African American	720 Participants n=5 Participants	725 Participants n=7 Participants	706 Participants n=5 Participants	706 Participants n=4 Participants	2857 Participants n=21 Participants
Race (NIH/OMB) White	2397 Participants n=5 Participants	2375 Participants n=7 Participants	2340 Participants n=5 Participants	2328 Participants n=4 Participants	9440 Participants n=21 Participants
Race (NIH/OMB) More than one race	30 Participants n=5 Participants	21 Participants n=7 Participants	65 Participants n=5 Participants	59 Participants n=4 Participants	175 Participants n=21 Participants
Race (NIH/OMB) Unknown or Not Reported	48 Participants n=5 Participants	53 Participants n=7 Participants	47 Participants n=5 Participants	50 Participants n=4 Participants	198 Participants n=21 Participants

PRIMARY outcome

Timeframe: Within 90 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 milliliter/kilogram (mL/kg) of any blood products at \<180 days.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	1.7 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	2.5 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: Within 150 days after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	3.1 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: Within 180 days after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	3.7 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	1.0 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	1.4 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: Within 150 days after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	1.7 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: Within 180 days after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	2.0 % of participants with MA-LRTI cases

PRIMARY outcome

Timeframe: From birth to 24 months of age

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

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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.
Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)	11.9 Percentage of participants Interval 10.8 to 13.0	10.3 Percentage of participants Interval 9.3 to 11.3

PRIMARY outcome

Timeframe: Within 1 Month after birth

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

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

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.
Percentage of Infant Participants With Neonatal Deaths (Safety)	0.1 Percentage of participants Interval 0.0 to 0.2	0.1 Percentage of participants Interval 0.0 to 0.3

PRIMARY outcome

Timeframe: At birth

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

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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.
Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)	5.6 Percentage of participants	6.7 Percentage of participants

PRIMARY outcome

Timeframe: Within 1 Month after birth

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

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

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.
Percentage of Infant Participants With Other Neonatal Events (Safety)	6.2 Percentage of participants	5.5 Percentage of participants

PRIMARY outcome

Timeframe: 1 minute 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.

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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3625 Participants 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.	Infant Participants: Placebo n=3606 Participants 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.
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	124 Participants
Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety) Score <4	49 Participants	44 Participants
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	3438 Participants

PRIMARY outcome

Timeframe: 5 minutes after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3618 Participants 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.	Infant Participants: Placebo n=3602 Participants 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.
Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety) Score <4	8 Participants	5 Participants
Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety) Score 4 to <7	29 Participants	27 Participants
Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety) Score 7 to 10	3581 Participants	3570 Participants

PRIMARY outcome

Timeframe: 10 minutes after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=999 Participants 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.	Infant Participants: Placebo n=999 Participants 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.
Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety) Score <4	0 Participants	0 Participants
Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety) Score 4 to <7	6 Participants	4 Participants
Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety) Score 7 to 10	993 Participants	995 Participants

PRIMARY outcome

Timeframe: From birth to 1 month of age

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

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.
Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)	38.0 Percentage of participants Interval 36.4 to 39.6	35.4 Percentage of participants Interval 33.9 to 37.0

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3568 Participants 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.	Infant Participants: Placebo n=3558 Participants 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.
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 Interval 15.5 to 17.9	16.4 Percentage of participants Interval 15.2 to 17.7
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 Interval 0.9 to 1.7	1.6 Percentage of participants Interval 1.2 to 2.1

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3568 Participants 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.	Infant Participants: Placebo n=3558 Participants 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.
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety) SAE	17.3 Percentage of participants Interval 16.1 to 18.6	17.2 Percentage of participants Interval 15.9 to 18.5
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety) NDCMC	2.1 Percentage of participants Interval 1.7 to 2.6	2.3 Percentage of participants Interval 1.9 to 2.9

PRIMARY outcome

Timeframe: From birth to 24 months of age

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

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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3659 Participants 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.	Infant Participants: Placebo n=3646 Participants 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.
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety) NDCMC	3.9 Percentage of participants Interval 3.3 to 4.6	4.5 Percentage of participants Interval 3.8 to 5.2
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety) SAE	19.0 Percentage of participants Interval 17.8 to 20.4	18.9 Percentage of participants Interval 17.6 to 20.2

PRIMARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3678 Participants 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.	Infant Participants: Placebo n=3651 Participants 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.
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Redness: Any	7.2 Percentage of participants Interval 6.4 to 8.1	0.2 Percentage of participants Interval 0.1 to 0.4
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Redness: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Swelling: Any	6.2 Percentage of participants Interval 5.4 to 7.0	0.2 Percentage of participants Interval 0.1 to 0.4
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Redness: Mild	5.0 Percentage of participants Interval 4.3 to 5.7	0.1 Percentage of participants Interval 0.0 to 0.3
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Redness: Moderate	2.1 Percentage of participants Interval 1.7 to 2.6	0.1 Percentage of participants Interval 0.0 to 0.3
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Redness: Severe	0.1 Percentage of participants Interval 0.0 to 0.3	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Swelling: Mild	4.1 Percentage of participants Interval 3.5 to 4.8	0.1 Percentage of participants Interval 0.0 to 0.3
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Swelling: Moderate	2.0 Percentage of participants Interval 1.6 to 2.5	0.1 Percentage of participants Interval 0.0 to 0.2
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Swelling: Severe	0.1 Percentage of participants Interval 0.0 to 0.2	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Swelling: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Pain at injection site: Any	40.7 Percentage of participants Interval 39.1 to 42.3	10.2 Percentage of participants Interval 9.2 to 11.2
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Pain at injection site: Mild	36.1 Percentage of participants Interval 34.6 to 37.7	9.3 Percentage of participants Interval 8.4 to 10.3
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Pain at injection site: Moderate	4.5 Percentage of participants Interval 3.8 to 5.2	0.9 Percentage of participants Interval 0.6 to 1.2
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Pain at injection site: Severe	0.1 Percentage of participants Interval 0.0 to 0.3	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety) Pain at injection site: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3678 Participants 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.	Infant Participants: Placebo n=3651 Participants 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.
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 Interval 0.0 to 0.2	0.1 Percentage of participants Interval 0.0 to 0.3
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fatigue: Any	46.1 Percentage of participants Interval 44.5 to 47.7	43.8 Percentage of participants Interval 42.2 to 45.4
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fatigue: Moderate	21.3 Percentage of participants Interval 20.0 to 22.7	19.6 Percentage of participants Interval 18.4 to 21.0
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fatigue: Severe	1.3 Percentage of participants Interval 1.0 to 1.8	1.4 Percentage of participants Interval 1.1 to 1.9
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fatigue: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Headache: Any	31.0 Percentage of participants Interval 29.5 to 32.5	27.6 Percentage of participants Interval 26.2 to 29.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Headache: Mild	20.2 Percentage of participants Interval 18.9 to 21.5	17.9 Percentage of participants Interval 16.7 to 19.2
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Headache: Moderate	10.4 Percentage of participants Interval 9.4 to 11.4	9.4 Percentage of participants Interval 8.5 to 10.4
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Nausea: Moderate	5.4 Percentage of participants Interval 4.7 to 6.1	5.2 Percentage of participants Interval 4.5 to 6.0
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Nausea: Severe	0.2 Percentage of participants Interval 0.1 to 0.4	0.2 Percentage of participants Interval 0.1 to 0.4
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Nausea: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Muscle pain: Moderate	8.6 Percentage of participants Interval 7.7 to 9.5	6.8 Percentage of participants Interval 6.0 to 7.7
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Muscle pain: Severe	0.4 Percentage of participants Interval 0.2 to 0.6	0.3 Percentage of participants Interval 0.2 to 0.6
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Muscle pain: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Joint pain: Any	11.6 Percentage of participants Interval 10.6 to 12.7	10.5 Percentage of participants Interval 9.5 to 11.6
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Joint pain: Moderate	4.9 Percentage of participants Interval 4.2 to 5.7	4.4 Percentage of participants Interval 3.8 to 5.2
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Joint pain: Severe	0.2 Percentage of participants Interval 0.1 to 0.4	0.1 Percentage of participants Interval 0.0 to 0.2
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Joint pain: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Vomiting: Any	7.9 Percentage of participants Interval 7.0 to 8.8	7.0 Percentage of participants Interval 6.2 to 7.8
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Vomiting: Moderate	1.3 Percentage of participants Interval 0.9 to 1.7	1.5 Percentage of participants Interval 1.2 to 2.0
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Vomiting: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Diarrhea: Any	11.3 Percentage of participants Interval 10.3 to 12.3	11.4 Percentage of participants Interval 10.4 to 12.5
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Diarrhea: Mild	9.1 Percentage of participants Interval 8.2 to 10.1	9.4 Percentage of participants Interval 8.4 to 10.4
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Diarrhea: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fever: >=38.0 degree C	2.6 Percentage of participants Interval 2.1 to 3.1	2.9 Percentage of participants Interval 2.4 to 3.5
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 Interval 1.3 to 2.1	1.5 Percentage of participants Interval 1.1 to 2.0
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 Interval 0.5 to 1.1	1.2 Percentage of participants Interval 0.8 to 1.6
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fever: >40.0 degree C	0.1 Percentage of participants Interval 0.0 to 0.2	0.1 Percentage of participants Interval 0.0 to 0.3
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Fatigue: Mild	23.5 Percentage of participants Interval 22.1 to 24.9	22.7 Percentage of participants Interval 21.4 to 24.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Headache: Severe	0.4 Percentage of participants Interval 0.2 to 0.7	0.4 Percentage of participants Interval 0.2 to 0.6
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Headache: Grade 4	0 Percentage of participants Interval 0.0 to 0.1	0 Percentage of participants Interval 0.0 to 0.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Nausea: Any	20.0 Percentage of participants Interval 18.7 to 21.3	19.3 Percentage of participants Interval 18.0 to 20.6
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Nausea: Mild	14.4 Percentage of participants Interval 13.3 to 15.6	13.9 Percentage of participants Interval 12.8 to 15.0
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Muscle pain: Any	26.6 Percentage of participants Interval 25.1 to 28.0	17.1 Percentage of participants Interval 15.9 to 18.4
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Muscle pain: Mild	17.6 Percentage of participants Interval 16.4 to 18.9	10.0 Percentage of participants Interval 9.0 to 11.0
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Joint pain: Mild	6.5 Percentage of participants Interval 5.7 to 7.3	6.0 Percentage of participants Interval 5.2 to 6.8
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Vomiting: Mild	6.4 Percentage of participants Interval 5.6 to 7.2	5.4 Percentage of participants Interval 4.7 to 6.1
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Vomiting: Severe	0.2 Percentage of participants Interval 0.1 to 0.4	0.1 Percentage of participants Interval 0.0 to 0.2
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Diarrhea: Moderate	2.0 Percentage of participants Interval 1.6 to 2.5	1.9 Percentage of participants Interval 1.4 to 2.4
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety) Diarrhea: Severe	0.1 Percentage of participants Interval 0.0 to 0.3	0.2 Percentage of participants Interval 0.1 to 0.4

PRIMARY outcome

Timeframe: From vaccination on Day 1 up to 1 month after vaccination

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

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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3698 Participants 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.	Infant Participants: Placebo n=3687 Participants 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.
Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)	14.0 Percentage of participants Interval 12.9 to 15.1	13.2 Percentage of participants Interval 12.2 to 14.4

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3698 Participants 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.	Infant Participants: Placebo n=3687 Participants 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.
Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)	16.6 Percentage of participants Interval 15.4 to 17.8	15.8 Percentage of participants Interval 14.6 to 17.0

SECONDARY outcome

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

Results are reported as confirmed by endpoint adjudication committee.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	1.1 %participants with hospitalization cases
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	1.2 %participants with hospitalization cases
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	1.3 %participants with hospitalization cases
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	1.9 %participants with hospitalization cases
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	0.9 %participants with hospitalization cases

SECONDARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	6.2 % of participants with MA-LRTI cases
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	8.8 % of participants with MA-LRTI cases
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	11.3 % of participants with MA-LRTI cases
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	13.0 % of participants with MA-LRTI cases
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	18.4 % of participants with MA-LRTI cases

SECONDARY outcome

Timeframe: Within 210, 240, 270 and 360 days after birth

Outcome measures

Outcome measures
Measure	Infant Participants: RSVpreF n=3585 Participants 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.	Infant Participants: Placebo n=3563 Participants 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.
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	4.0 % of participants with MA-LRTI cases
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	4.2 % of participants with MA-LRTI cases
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	5.1 % of participants with MA-LRTI cases
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	4.4 % of participants with MA-LRTI cases

Adverse Events

Maternal Participants: RSVpreF

Serious events: 613 serious events

Other events: 2755 other events

Deaths: 1 deaths

Maternal Participants: Placebo

Serious events: 581 serious events

Other events: 2339 other events

Deaths: 0 deaths

Infant Participants: RSVpreF

Serious events: 697 serious events

Other events: 674 other events

Deaths: 8 deaths

Infant Participants: Placebo

Serious events: 689 serious events

Other events: 598 other events

Deaths: 14 deaths

Serious adverse events

Other adverse events

Additional Information

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Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee Pfizer has the right to review disclosures, requesting a delay of less than 60 days. Investigator will postpone single center publications until after disclosure of pooled data (all sites), less than 12 months from study completion/termination at all participating sites. Investigator may not disclose previously undisclosed confidential information other than study results.
Publication restrictions are in place

Restriction type: OTHER