RSVpreF

Describe pre-specified local reactions in children 5 to \<18 years of age with chronic medical conditions

Describe pre-specified local reactions in children 5 to \<18 years of age with immunocompromising conditions

Describe pre-specified systemic events in children 5 to \<18 years of age with chronic medical conditions

Describe pre-specified systemic events in children 5 to \<18 years of age with immunocompromising conditions

Describe AEs in children 5 to \<18 years of age with chronic medical conditions

Describe AEs in children 5 to \<18 years of age with immunocompromising conditions

Describe SAEs in children 5 to \<18 years of age with chronic medical conditions

Describe SAEs in children 5 to \<18 years of age with immunocompromising conditions

Describe NDCMCs in children 5 to \<18 years of age with chronic medical conditions

Describe NDCMCs in children 5 to \<18 years of age with immunocompromising conditions

Demonstrate that the immune responses elicited by RSVpreF in children 5 to \<18 years of age with chronic medical conditions are noninferior to the immune responses in adults ≥60 years of age

Demonstrate that the immune responses elicited by RSVpreF in children 5 to \<18 years of age with chronic medical conditions are noninferior to the immune responses in adults ≥60 years of age. Seroresponse is defined as a postvaccination NT ≥4 times the lower limit of quantitation (LLOQ) if the prevaccination titer is below the LLOQ; or a ≥4-fold rise from prevaccination if the prevaccination titer is ≥ LLOQ

Describe the immune responses elicited by 1 or 2 doses of RSVpreF in children 5 to \<18 years of age with immunocompromising conditions

Describe the immune responses elicited by 1 or 2 doses of RSVpreF in children 5 to \<18 years of age with immunocompromising conditions

Describe the immune responses elicited by 1 or 2 doses of RSVpreF in children 5 to \<18 years of age with immunocompromising conditions

Describe local reactions following investigational product administration

Describe systemic events following investigational product administration

Describe AEs occurring through 1 month following administration of investigational product

Describe SAEs through 3 months following administration of investigational product

Describe prompted local reactions following investigational product administration

Describe prompted systemic events following investigational product administration

Demonstrate that the immune responses to RSVpreF in this study participant are similar to those in Study C3671013 Japanese older adults

Pain at the injection site, redness, and swelling

Fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain, and joint pain

Local reactions included redness, swelling and pain at injection site. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit=0.5 centimeter (cm). Redness and swelling were graded as mild: \> 2.0 cm to 5.0 cm, moderate: \> 5.0 cm to 10.0 cm, severe: \>10.0 cm. Pain at injection site was graded as mild: did not interfere with activity, moderate: interfered with activity, severe: prevented daily activity. Any local reaction: any redness, any swelling, or pain at the injection site of at least mild severity. Exact 2-sided 95% confidence interval (CI) was based on the Clopper and Pearson method.

Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. Fever defined as oral temperature \>=38.0 degrees Celsius (deg C) and categorized as mild: \>=38.0 to 38.4 deg C, moderate: \>38.4 to 38.9 deg C, severe: \>38.9 to 40.0 deg C, and Grade 4: \>40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Exact 2-sided 95% CI was based on the Clopper and Pearson method. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were reported in this outcome measure.

An SAE was defined as an AE that, at any dose met one of the following criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity; was a congenital anomaly/birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic; other significant medical events as judged by investigator. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

A NDCMC was defined as a disease or medical condition that was not identified prior to study start and was expected to be persistent or otherwise long-lasting in its effects. Newly diagnosed chronic medical condition did not include illnesses considered to be temporary conditions. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

GMTs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below the lower limit of quantification (LLOQ) were set to 0.5\*LLOQ for analysis.

GMTs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5\*LLOQ for analysis.

Fold rises was defined as ratios of the results after vaccination to the results before vaccination. GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution).

Local reactions included redness, swelling, and pain at injection site and were recorded in electronic diary (e-diary). Redness and swelling were measured by the maternal participant and recorded in measuring device units (mdu) in the e-diary (range: 1 to 21). 1 mdu = 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 severe pain at the injection site). Grade 4 reactions were classified by the investigator or medically qualified designee.

Systemic events included fever, fatigue, headache, nausea, muscle pain, joint pain, vomiting and diarrhea and were recorded by participants in the e-diary. Fever was defined as an oral temperature greater than or equal to (\>=) 38.0 degree Celsius (C) and classified as mild (38.0 to 38.4 degree C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C) 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 loose stools 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 designee.

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.

AESIs 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 prior to/during delivery and post delivery. For maternal participants, the following were considered as protocol defined AESIs: diagnosis of Guillain-Barré syndrome; diagnosis of acute polyneuropathy without an underlying etiology; hypertensive disorders of pregnancy; preterm delivery (delivery at \<37 0/7 weeks' gestation) and atrial fibrillation. AESIs was to be recorded as an AE or serious adverse event (SAE) on the case report form (CRF).

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.

AESIs 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 infants at birth. For infant participants the following were considered as protocol defined AESIs: preterm birth (born at \<37 0/7 week's gestation); birth weight 1001-2500 grams (g); developmental delay. Extremely preterm birth (born at \<28 0/7 week's gestation) and extremely low birth weight (less than or equal to \[\<=\] 1000 g) were reported as serious AESIs.

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

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

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.

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.

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.

GA at birth was collected as:\>=24 to \<28 weeks, \>=28 to \<34 weeks, \>=34 to \<37 weeks, \>=37 to \<42 weeks, and \>=42 weeks.

Length of hospitalization at birth refers to the amount of time the infant remains admitted to the healthcare facility immediately following delivery and if that length of time is greater than or less than 72 hours. Postnatal standard of care procedures in South Africa were as follows: healthy newborns and their mothers were typically discharged within 24 hours after an uncomplicated vaginal delivery, or within 72 hours following an uncomplicated Caesarean section. These practices were supported by the Guidelines for Maternity Care in South Africa.

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 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. NDCMCs were reported as both AEs and SAEs.

Local reactions included pain at injection site, redness and swelling, recorded by participants in an electronic diary (e-diary). Pain at injection site was graded as mild: did not interfere with activity; moderate: interfered with activity and severe: prevented daily activity. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit =0.5 centimeter (cm). Redness and swelling were graded as mild: \>2.5 cm to 5.0 cm; moderate: \>5.0 cm to 10.0 cm; severe: \>10 cm.

Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. These were recorded by participants in an e-diary. Fever defined as oral temperature \>=38.0 degrees Celsius (deg C) and categorized as mild: \>=38.0 to 38.4 deg C, moderate: \>38.4 to 38.9 deg C and severe: \>38.9 to 40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity.

An AE was defined as any untoward medical occurrence in a 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. AEs included both serious and all non-serious adverse events.

A NDCMC was defined as a disease or medical condition that was not identified prior to study start and was expected to be persistent or otherwise long-lasting in its effects. Newly diagnosed chronic medical condition did not include illnesses considered to be temporary conditions.

An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention. An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect and was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical event were included in this outcome measure.

In this outcome measure, GMTs for RSV A and RSV B neutralizing titers (NTs) are reported. In statistical section, GMT ratio estimated by the ratio of the GMTs for RSV A and RSV B serum NTs at 1 month after vaccination with RSVpreF in current study C3671023 participants to that in study C3671013 adults \>=60 years of age, is reported. GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on Student t distribution).

Seroresponse was defined as achieving a \>=4-fold rise from baseline (before vaccination), if the baseline measurement was above the lower limit of quantitation (LLOQ). If the baseline measurement was below the LLOQ, a postvaccination assay result \>=4\* LLOQ was considered a seroresponse.

Local reactions included pain at injection site, redness and swelling, recorded by participants in an e-diary. Pain at injection site was graded as mild: did not interfere with activity; moderate: interfered with activity and severe: prevented daily activity. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit=0.5 cm. Redness and swelling were graded as mild: \> 2.0 cm to 5.0 cm; moderate: \> 5.0 cm to 10.0 cm and severe: \> 10 cm.

Local reactions included pain at injection site, redness and swelling, recorded by participants in an e-diary. Pain at injection site was graded as mild: did not interfere with activity; moderate: interfered with activity and severe: prevented daily activity. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit = 0.5 cm. Redness and swelling were graded as mild: \>2.0 cm to 5.0 cm; moderate: \>5.0 cm to 10.0 cm and severe: \>10 cm.

Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. These were recorded by participants in an e-diary. Fever defined as oral temperature \>=38.0 degrees Celsius (deg C) and categorized as mild: \>=38.0 to 38.4 deg C, moderate: \>38.4 to 38.9 deg C and severe: \>38.9 to 40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity.

Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. These were recorded by participants in an e-diary. Fever defined as oral temperature \>=38.0 degrees Celsius (deg C) and categorized as mild: \>=38.0 to 38.4 deg C, moderate: \>38.4 to 38.9 deg C and severe: \>38.9 to 40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity.

An AE was defined as any untoward medical occurrence in a 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. AEs included both serious and all non-serious adverse events.

A NDCMC was defined as a disease or medical condition that was not identified prior to study start and was expected to be persistent or otherwise long-lasting in its effects. Newly diagnosed chronic medical condition did not include illnesses considered to be temporary conditions.

An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention. An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect and was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical event were included in this outcome measure.

GMT of RSV A and RSV B before vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\*LLOQ. GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution).

GMT of RSV A and RSV B before vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\*LLOQ. GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution).

GMT of RSV A and RSV B before vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\*LLOQ. GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution).

Local reactions were collected at the RSVpreF or placebo injection site after Vaccination 1 and Vaccination 2 and were recorded by participants using electronic diary (e-diary). Local reactions included redness, swelling and pain at injection site. Redness and swelling were measured and recorded in measuring device units where, 1 measuring device unit =0.5 centimeter (cm) and were graded as mild (greater than \[\>\] 2.0 to 5.0 cm), moderate (\>5.0 to 10.0 cm), and severe (\>10.0 cm). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), and severe (prevented daily activity). Percentage of participants reporting local reactions at injection site in Coadministration Group, and Sequential-Administration Group and associated 2-sided 95% confidence interval (CI) based on Clopper and Pearson method was presented in this outcome measure (OM). Safety population=all enrolled participants who received study intervention (RSVpreF, placebo).

Systemic events included fever, fatigue, headache, nausea, vomiting, diarrhea, muscle pain and joint pain and were recorded by participants using an e-diary. Fever was defined as an oral temperature \>=38.0 degree Celsius (deg C) and categorized as \>=38.0 to 38.4 deg C (mild), \>38.4 to 38.9 deg C (moderate), \>38.9 to 40.0 deg C (severe) and \>40.0 deg C (grade 4). Fatigue, headache, nausea, muscle pain and joint pain were graded as mild (did not interfere with activity), moderate (some interference with activity) and severe (prevented daily routine activity). Vomiting was graded mild: 1 to 2 times in 24 hours (h), moderate: \>2 times in 24h, and severe: required intravenous hydration. Diarrhea was graded mild: 2 to 3 loose stools in 24h, moderate: 4 to 5 loose stools in 24h and severe: 6 or more loose stools in 24h. Percentage of participants with systemic events within 7 days after each vaccination and the associated 2-sided 95% CI based on the Clopper and Pearson method was presented.

An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Percentage of participants reporting AEs within 1 month after Vaccination 1 were reported in this outcome measure. Exact 2-sided CI was calculated using the Clopper and Pearson method. Only AEs collected by non-systematic assessment (i.e., excluding local reactions and systemic events) were reported in this outcome measure.

An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Percentage of participants reporting AEs within 1 month after Vaccination 2 were reported in this outcome measure. Exact 2-sided CI was calculated using the Clopper and Pearson method. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were reported in this outcome measure.

An SAE was defined as an AE that, at any dose: resulted in death; was life-threatening; required inpatient hospitalization or prolongation of existing hospitalization; resulted in persistent disability/incapacity; was a congenital anomaly/birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic or that was considered to be an important medical event. Percentage of participants with SAEs and the associated 2-sided 95% CI based on the Clopper and Pearson method was presented. Percentage of participants reporting SAEs within 1 month after Vaccination 1 were reported in this outcome measure.

An SAE was defined as an AE that, at any dose: resulted in death; was life-threatening; required inpatient hospitalization or prolongation of existing hospitalization; resulted in persistent disability/incapacity; was a congenital anomaly/birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic or that was considered to be an important medical event. Percentage of participants with SAEs and the associated 2-sided 95% CI based on the Clopper and Pearson method was presented. Percentage of participants reporting SAEs within 1 month after Vaccination 2 were reported in this outcome measure.

Geometric mean titer (GMT) of RSV A and RSV B neutralizing titers for the Coadministration Group and Sequential-Administration Group were reported in this outcome measure in descriptive data section. GMTs and the 2-sided 95% CI were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on Student's t distribution). Assay results below the lower limit of quantification (LLOQ) were set to 0.5\*LLOQ. Geometric mean ratio (GMR) was reported in the statistical analysis section and was calculated as ratio of GMTs in the Coadministration Group to the Sequential-Administration Group.

GMTs of strain-specific HAI titers for the Coadministration Group and Sequential-Administration Group were reported in this outcome measure in descriptive data section. GMTs and the 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on Student's t distribution). Assay results below the LLOQ were set to 0.5\*LLOQ. GMR was reported in the statistical analysis section and was calculated as ratio of GMT in the Coadministration Group to the Sequential-Administration Group.

Geometric mean titer (GMT) of RSV A and RSV B neutralizing antibodies were calculated by exponentiating the mean logarithm of the titers and the corresponding 95% confidence interval (CI) was based on the Student t distribution. GMTs were reported in the descriptive section. Geometric mean ratios (GMRs) for each RSV vaccine lot comparison (Group 1/Group 2, Group 1/Group 3, and Group 2/Group 3) for RSV A and RSV B neutralizing antibody titers was calculated and reported in statistical analysis.

An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. AEs included both serious and all non-serious adverse events excluding local reactions and systemic events. SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; required inpatient hospitalization or prolongation of existing hospitalization; life-threatening ; persistent or significant disability/incapacity; congenital anomaly/birth defect and suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)-confirmed RSV A and/or RSV B- associated acute respiratory illness (ARI) is assessed. LRTI-RSV is defined as an ARI with 2 or more of the lower respiratory signs/symptoms lasting more than 1 day during the same illness, plus RT-PCR-confirmed RSV infection within 7 days of ARI symptom onset. Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)-confirmed RSV A and/or RSV B- associated acute respiratory illness (ARI) is assessed. LRTI-RSV is defined as an ARI with 3 or more of the lower respiratory signs/symptoms lasting more than 1 day during the same illness, plus RT-PCR-confirmed RSV infection within 7 days of ARI symptom onset.

Local reactions included pain at injection site, redness and swelling recorded by participants in an e-diary. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit =0.5 cm and graded as mild: 2.5 to 5.0 cm, moderate: \> 5.0 to 10.0 cm and severe: \>10 cm. Pain at injection site was graded as mild: did not interfere with daily activity, moderate: interfere with daily activity and severe: prevented daily activity

Systemic reactions:fever, fatigue/tiredness, headache, nausea, muscle pain, joint pain, vomiting, diarrhea and any systemic event recorded by participants in an e-diary. Fever: greater than equal to (\>=)38.0 degrees (deg) Celsius (C), mild (\>=38.0 to 38.4 deg C, \>38.4 to 38.9 deg C), moderate (\>38.9 to 40.0 deg C and \>40.0 deg C), severe (\>38.9 deg C to 40.0 deg C) and grade 4 (\>40.0 deg C). Fatigue, headache, nausea, muscle pain and joint pain were graded as mild: did not interfere with activity, moderate: some interference with activity and severe: prevented daily routine activity. Vomiting was graded as mild: 1 to 2 times in 24 hours(h), moderate: \>2 times in 24h and severe: requires intravenous hydration. Diarrhea was graded as mild: 2 to 3 loose stools in 24h, moderate: 4 to 5 loose stools in 24h and severe: 6 or more loose stools in 24h.

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. AEs included both serious and non-serious adverse events.

SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

An NDCMC is defined as a disease or medical condition, not previously identified, that is expected to be persistent or otherwise long-lasting in its effects (eg, asthma).

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean Titers (GMTs), and geometric mean fold rise (GMFR). The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

Local reactions included pain at injection site, redness and swelling recorded by participants in an e-diary. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit =0.5 cm and graded as mild: 2.5 to 5.0 cm, moderate: \> 5.0 to 10.0 cm and severe: \>10 cm. Pain at injection site was graded as mild: did not interfere with daily activity, moderate: interfere with daily activity and severe: prevented daily activity

Systemic reactions:fever, fatigue/tiredness, headache, nausea, muscle pain, joint pain, vomiting, diarrhea and any systemic event recorded by participants in an e-diary. Fever: greater than equal to (\>=)38.0 degrees (deg) Celsius (C), mild (\>=38.0 to 38.4 deg C, \>38.4 to 38.9 deg C), moderate (\>38.9 to 40.0 deg C and \>40.0 deg C), severe (\>38.9 deg C to 40.0 deg C) and grade 4 (\>40.0 deg C). Fatigue, headache, nausea, muscle pain and joint pain were graded as mild: did not interfere with activity, moderate: some interference with activity and severe: prevented daily routine activity. Vomiting was graded as mild: 1 to 2 times in 24 hours(h), moderate: \>2 times in 24h and severe: requires intravenous hydration. Diarrhea was graded as mild: 2 to 3 loose stools in 24h, moderate: 4 to 5 loose stools in 24h and severe: 6 or more loose stools in 24h.

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. AEs included both serious and non-serious adverse events.

SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

An NDCMC is defined as a disease or medical condition, not previously identified, that is expected to be persistent or otherwise long-lasting in its effects (eg, asthma).

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean Titers (GMTs), and geometric mean fold rise (GMFR). The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

Local reactions included pain at injection site, redness and swelling recorded by participants in an e-diary. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit =0.5 cm and graded as mild: 2.5 to 5.0 cm, moderate: \> 5.0 to 10.0 cm and severe: \>10 cm. Pain at injection site was graded as mild: did not interfere with daily activity, moderate: interfere with daily activity and severe: prevented daily activity.

Systemic reactions:fever, fatigue/tiredness, headache, nausea, muscle pain, joint pain, vomiting, diarrhea and any systemic event recorded by participants in an e-diary. Fever: greater than equal to (\>=)38.0 degrees (deg) Celsius (C), mild (\>=38.0 to 38.4 deg C, \>38.4 to 38.9 deg C), moderate (\>38.9 to 40.0 deg C and \>40.0 deg C), severe (\>38.9 deg C to 40.0 deg C) and grade 4 (\>40.0 deg C). Fatigue, headache, nausea, muscle pain and joint pain were graded as mild: did not interfere with activity, moderate: some interference with activity and severe: prevented daily routine activity. Vomiting was graded as mild: 1 to 2 times in 24 hours(h), moderate: \>2 times in 24h and severe: requires intravenous hydration. Diarrhea was graded as mild: 2 to 3 loose stools in 24h, moderate: 4 to 5 loose stools in 24h and severe: 6 or more loose stools in 24h.

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. AEs included both serious and non-serious adverse events.

SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

An NDCMC is defined as a disease or medical condition, not previously identified, that is expected to be persistent or otherwise long-lasting in its effects (eg, asthma).

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean NT ratios. The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean NT ratios. The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean of individual NT ratios (GMIR). The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean NT ratios. The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean NT ratios. The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

RSV A and RSV B neutralizing titers (NT), expressed as Geometric Mean of individual NT ratios (GMIR). The NTs were calculated as the interpolated reciprocal of the serum dilution resulting in 50% reduction in the number of viral focus forming units when compared to the control without test serum.

Local reactions included pain at injection site, redness and swelling recorded by participants in an e-diary. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit =0.5 cm and graded as mild: 2.5 to 5.0 cm, moderate: \> 5.0 to 10.0 cm and severe: \>10 cm. Pain at injection site was graded as mild: did not interfere with daily activity, moderate: interfere with daily activity and severe: prevented daily activity.

Local reactions included pain at injection site, redness and swelling recorded by participants in an e-diary. Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit =0.5 cm and graded as mild: 2.5 to 5.0 cm, moderate: \> 5.0 to 10.0 cm and severe: \>10 cm. Pain at injection site was graded as mild: did not interfere with daily activity, moderate: interfere with daily activity and severe: prevented daily activity.

Systemic reactions:fever, fatigue/tiredness, headache, nausea, muscle pain, joint pain, vomiting, diarrhea and any systemic event recorded by participants in an e-diary. Fever: greater than equal to (\>=)38.0 degrees (deg) Celsius (C), mild (\>=38.0 to 38.4 deg C, \>38.4 to 38.9 deg C), moderate (\>38.9 to 40.0 deg C and \>40.0 deg C), severe (\>38.9 deg C to 40.0 deg C) and grade 4 (\>40.0 deg C). Fatigue, headache, nausea, muscle pain and joint pain were graded as mild: did not interfere with activity, moderate: some interference with activity and severe: prevented daily routine activity. Vomiting was graded as mild: 1 to 2 times in 24 hours(h), moderate: \>2 times in 24h and severe: requires intravenous hydration. Diarrhea was graded as mild: 2 to 3 loose stools in 24h, moderate: 4 to 5 loose stools in 24h and severe: 6 or more loose stools in 24h.

Systemic reactions:fever, fatigue/tiredness, headache, nausea, muscle pain, joint pain, vomiting, diarrhea and any systemic event recorded by participants in an e-diary. Fever: greater than equal to (\>=)38.0 degrees (deg) Celsius (C), mild (\>=38.0 to 38.4 deg C, \>38.4 to 38.9 deg C), moderate (\>38.9 to 40.0 deg C and \>40.0 deg C), severe (\>38.9 deg C to 40.0 deg C) and grade 4 (\>40.0 deg C). Fatigue, headache, nausea, muscle pain and joint pain were graded as mild: did not interfere with activity, moderate: some interference with activity and severe: prevented daily routine activity. Vomiting was graded as mild: 1 to 2 times in 24 hours(h), moderate: \>2 times in 24h and severe: requires intravenous hydration. Diarrhea was graded as mild: 2 to 3 loose stools in 24h, moderate: 4 to 5 loose stools in 24h and severe: 6 or more loose stools in 24h.

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. AEs included both serious and non-serious adverse events.

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. AEs included both serious and non-serious adverse events.

SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

An NDCMC is defined as a disease or medical condition, not previously identified, that is expected to be persistent or otherwise long-lasting in its effects (eg, asthma).

An NDCMC is defined as a disease or medical condition, not previously identified, that is expected to be persistent or otherwise long-lasting in its effects (eg, asthma).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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.

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.

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.

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 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.

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.

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.

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.

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.

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.

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.