A Phase 3 interventional study of RSVpreF and Placebo in Respiratory Tract Infection, sponsored by Pfizer. Completed at 464 sites in 18 countries. Open to female participants aged 0 Years to 49 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-02-11.
Sponsored by Pfizer · Phase 3, Interventional, and Prevention
This randomized, double-blinded, placebo-controlled Phase 3 study is designed to evaluate the efficacy and safety of maternal immunization with RSVpreF against medically attended lower respiratory tract illness (MA-LRTI) in infants.
This is a Phase 3, multicenter, randomized, double-blinded, placebo-controlled study to assess the efficacy, safety, and immunogenicity of RSVpreF or placebo (1:1 randomization) in infants born to healthy women vaccinated during pregnancy, as well as the safety and immunogenicity in the pregnant women. This will be a global study which will span multiple RSV seasons.
751 studies on the registry are indexed under Respiratory Tract Infections; 114 are open to participants now.
This study's enrollment of 14,727 is above the median of 200 across 540 interventional studies indexed under Respiratory Tract Infections.
Browse Respiratory Tract Infections studies →Pfizer is the lead sponsor of 3,334 studies on the registry; 149 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 391 (65%) have results posted.
Counted across the registry records on this site, refreshed daily.
Inclusion Criteria - Maternal Participants:
Inclusion Criteria -Infant Participants:
Exclusion Criteria - Maternal Participants:
Current pregnancy complications or abnormalities at the time of consent that will increase the risk associated with the participation in and completion of the study, including but not limited to the following:
Prior pregnancy complications or abnormalities at the time of consent, based on the investigator's judgment, that will increase the risk associated with the participation in and completion of the study, including but not limited to the following:
Exclusion Criteria -Infant Participants:
o Infant who is a direct descendant (eg, child or grandchild) of the study personnel.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
RSVpreF
Biological: RSVpreF
Placebo
Biological: Placebo
RSV vaccine (RSVpreF)
Placebo
Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: infant with an MA-RTI visit with age related fast breathing (respiratory rate \[RR\] more than or equal to \[\>=\] 60 breaths per minute \[bpm\] for less than \[\<\] 2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or oxygen saturation (SpO2) \<95 percent (%) or chest wall indrawing and RSV positive test results by reverse transcription-polymerase chain reaction (RT-PCR) testing of midturbinate nasal swab samples.
Time frame: Within 90 days after birth
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Time frame: Within 120 days after birth
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Time frame: Within 150 days after birth
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Time frame: Within 180 days after birth
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or intensive care unit (ICU) admission for more than (\>) 4 hours or failure to respond/unconscious.
Time frame: Within 90 days after birth
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.
Time frame: Within 120 days after birth
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.
Time frame: Within 150 days after birth
Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. Severe MA-LRTI cases were a subset of MA-LRTI cases, and all severe MA-LRTI cases were included MA-LRTI cases. Severe MA-LRTI case was an RSV positively adjudicated event which met the following defined criteria: an infant with an MA-RTI visit and aged associated fast breathing (RR \>=70 bpm for \<2 months of age \[\<60 days of age\], \>=60 bpm for \>=2 months to \<12 months of age, or \>=50 bpm for \>=12 months to 24 months of age) or SpO2 \<93% or high-flow nasal cannula or mechanical ventilation (i.e., invasive or non-invasive) or ICU admission for \>4 hours or failure to respond/unconscious.
Time frame: Within 180 days after birth
Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety)
AESI are a subset of targeted medical events based on review of known pharmacology, toxicology findings, possible class effects, published literature, and signals arising from safety data assessments, and on population under study. AESIs were based on targeted medical events associated with pregnant maternal participants and their infants prior to/during delivery and at birth. For infant participants the following were considered as protocol defined AESIs: Preterm birth (born at \<37 weeks gestation); birth weight 1001-2500 grams; developmental delay; positive viral (polymerase chain reaction \[PCR\] or antigen-based) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when not reported during MA-RTI visit, were reported as SARS-CoV-2 test positive. Extremely preterm birth (\<28 weeks) and extremely low birth weight (=\<1000 grams \[g\]) were reported as serious AESIs.
Time frame: From birth to 24 months of age
Percentage of Infant Participants With Neonatal Deaths (Safety)
Neonatal death was defined as the death of a live-born infant that occurred within a month after birth.
Time frame: Within 1 Month after birth
Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety)
Congenital malformations/ anomalies were defined as structural or functional anomalies that occurred during intrauterine life and could be identified prenatally, at birth or later in life.
Time frame: At birth
Percentage of Infant Participants With Other Neonatal Events (Safety)
Other Neonatal problem included dysmaturity, neonatal illness, hospitalization, drug therapies, and neonatal death.
Time frame: Within 1 Month after birth
Number of Infant Participants According to Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) Score at 1 Minute After Birth (Safety)
APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.
Time frame: 1 minute after birth
Number of Infant Participants According to APGAR Score at 5 Minutes After Birth (Safety)
APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.
Time frame: 5 minutes after birth
Number of Infant Participants According to APGAR Score at 10 Minutes After Birth (Safety)
APGAR was a fast evaluation technique used to evaluate a newborn baby's overall health. APGAR stands for (A) Appearance (skin coloration), (P) Pulse (heart rate), (G) Grimace (reflex response), (A) Activity (muscle tone) and (R) Respiration (breathing). Each component was given a score of 0, 1, or 2; after summing up scores for each component a total possible score was of 0 (worst condition) to 10 (best condition), where higher scores indicate better health. A score of 7 to 10 was good, 4 to \<7 was moderate, and \<4 was poor.
Time frame: 10 minutes after birth
Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety)
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Time frame: From birth to 1 month of age
Percentage of Infant Participants With Serious Adverse Events (SAEs) and Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Birth Through 6 Months of Age (Safety)
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
Time frame: From birth to 6 months of age
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 12 Months of Age (Safety)
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
Time frame: From birth to 12 months of age
Percentage of Infant Participants With SAEs and NDCMCs From Birth Through 24 Months of Age (Safety)
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
Time frame: From birth to 24 months of age
Percentage of Maternal Participants With Prespecified Local Reactions Within 7 Days After Vaccination (Safety)
Local reactions included redness, swelling, and pain at injection site and were recorded in electronic diary (e-diary). Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit= 0.5 centimetre (cm). Redness and swelling were graded as mild (\>2.0 to 5.0 cm), moderate (\>5.0 to 10.0 cm), severe (\>10.0 cm) and grade 4 (necrosis or exfoliative dermatitis for redness and necrosis for swelling). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization for the severe pain at the injection site). Grade 4 reactions were classified by the investigator or medically qualified person.
Time frame: From Day 1 to Day 7 after vaccination
Percentage of Maternal Participants With Prespecified Systemic Events Within 7 Days After Vaccination (Safety)
Systemic events included: fever, fatigue, headache, nausea, muscle pain, joint pain, vomiting and diarrhea and were recorded by participants in an e-diary. Fever was defined as an oral temperature \>=38.0 degree Celsius \[C\]) and classified as mild (38.0 to 38.4), moderate (38.5 to 38.9), severe (39.0 to 40.0) and grade 4 (\>40.0 degree C). Headache, nausea, fatigue, muscle pain and joint pain were graded as mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily activity). Vomiting: mild (1-2 times in 24 hours \[H\]), moderate (\>2 times in 24 H), severe (required intravenous \[IV\] hydration). Diarrhea: mild (2-3 loose stools in 24 H), moderate (4-5 loose stools in 24 H), severe (\>=6 in 24 H). For all systemic events except fever, Grade 4= emergency room visit or hospitalization. Grade 4 events were classified by investigator or medically qualified person.
Time frame: From Day 1 to Day 7 after vaccination
Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety)
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were included in this outcome measure.
Time frame: From vaccination on Day 1 up to 1 month after vaccination
Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety)
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event.
Time frame: From vaccination on Day 1 up to 6 months after delivery (maximum up to 10 months)
Percentage of Infant Participants With Cases of Hospitalization Due to RSV Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)
Results are reported as confirmed by endpoint adjudication committee.
Time frame: Within 90, 120, 150, 180 and 360 days after birth
Percentage of Infant Participants With MA-LRTI Cases Due to Any Cause With Protocol Defined Criteria Occurring Within 90, 120, 150, 180 and 360 Days After Birth (Efficacy)
MA-LRTI cases due to any cause was defined as an infant with a MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing.
Time frame: Within 90, 120, 150, 180 and 360 days after birth
Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 210, 240, 270 and 360 Days After Birth (Efficacy)
Results are presented as confirmed by endpoint adjudication committee. MA-LRTI case: Infant with an MA-RTI visit with age related fast breathing (RR \>=60 bpm for \<2 months of age \[\<60 days of age\], \>=50 bpm for \>=2 months to \<12 months of age, or \>=40 bpm for \>=12 months to 24 months of age) or SpO2 \<95% or chest wall indrawing and RSV positive test results by RT-PCR testing of midturbinate nasal swab samples.
Time frame: Within 210, 240, 270 and 360 days after birth
| Milestone | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|---|---|
| Started | 3712 | 3708 | 3661 | 3646 |
| Safety population | 3698 | 3687 | 3659 | 3646 |
| Completed | 3516 | 3509 | 3318 | 3294 |
| Not completed | 196 | 199 | 343 | 352 |
| Withdrew: Adverse event | 0 | 1 | 0 | 0 |
| Withdrew: Death | 1 | 0 | 8 | 14 |
| Withdrew: Lost to follow-up | 93 | 88 | 224 | 211 |
| Withdrew: No longer met eligibility criteria | 1 | 0 | 0 | 0 |
| Withdrew: Other | 15 | 11 | 34 | 45 |
| Withdrew: Physician decision | 1 | 0 | 1 | 1 |
| Withdrew: Protocol violation | 0 | 1 | 0 | 0 |
| Withdrew: Withdrawal by subject | 71 | 77 | 0 | 0 |
| Withdrew: Withdrawal by parent/guardian | 0 | 0 | 74 | 81 |
| Withdrew: Randomized but not vaccinated | 13 | 21 | 0 | 0 |
| Withdrew: Mother vaccinated but unblinded during study | 1 | 0 | 2 | 0 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Medically Attended Lower Respiratory Tract Illness (MA-LRTI) Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy) | 0.7 | 1.7 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy) | 1.1 | 2.5 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy) | 1.5 | 3.1 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy) | 1.9 | 3.7 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 90 Days After Birth (Efficacy) | 0.2 | 1.0 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 120 Days After Birth (Efficacy) | 0.4 | 1.4 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 150 Days After Birth (Efficacy) | 0.5 | 1.7 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Severe MA-LRTI Cases Due to RSV Occurring Within 180 Days After Birth (Efficacy) | 0.6 | 2.0 |
AESI are a subset of targeted medical events based on review of known pharmacology, toxicology findings, possible class effects, published literature, and signals arising from safety data assessments, and on population under study. AESIs were based on targeted medical events associated with pregnant maternal participants and their infants prior to/during delivery and at birth. For infant participants the following were considered as protocol defined AESIs: Preterm birth (born at \<37 weeks gestation); birth weight 1001-2500 grams; developmental delay; positive viral (polymerase chain reaction \[PCR\] or antigen-based) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when not reported during MA-RTI visit, were reported as SARS-CoV-2 test positive. Extremely preterm birth (\<28 weeks) and extremely low birth weight (=\<1000 grams \[g\]) were reported as serious AESIs.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Adverse Events of Special Interest (AESI) (Safety) | 11.9 (10.8 to 13.0) | 10.3 (9.3 to 11.3) |
Neonatal death was defined as the death of a live-born infant that occurred within a month after birth.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Neonatal Deaths (Safety) | 0.1 (0.0 to 0.2) | 0.1 (0.0 to 0.3) |
Congenital malformations/ anomalies were defined as structural or functional anomalies that occurred during intrauterine life and could be identified prenatally, at birth or later in life.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Congenital Malformations/Anomalies (Safety) | 5.6 | 6.7 |
Other Neonatal problem included dysmaturity, neonatal illness, hospitalization, drug therapies, and neonatal death.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Other Neonatal Events (Safety) | 6.2 | 5.5 |
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.
| Participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Score <4 | 49 | 44 |
| Score 4 to <7 | 135 | 124 |
| Score 7 to 10 | 3441 | 3438 |
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.
| Participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Score <4 | 8 | 5 |
| Score 4 to <7 | 29 | 27 |
| Score 7 to 10 | 3581 | 3570 |
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.
| Participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Score <4 | 0 | 0 |
| Score 4 to <7 | 6 | 4 |
| Score 7 to 10 | 993 | 995 |
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| Percentage of Infant Participants With Adverse Events (AEs) From Birth to 1 Month of Age (Safety) | 38.0 (36.4 to 39.6) | 35.4 (33.9 to 37.0) |
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| SAE | 16.7 (15.5 to 17.9) | 16.4 (15.2 to 17.7) |
| NDCMC | 1.3 (0.9 to 1.7) | 1.6 (1.2 to 2.1) |
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| SAE | 17.3 (16.1 to 18.6) | 17.2 (15.9 to 18.5) |
| NDCMC | 2.1 (1.7 to 2.6) | 2.3 (1.9 to 2.9) |
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event. An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or otherwise long-lasting in its effects.
| Percentage of participants | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| SAE | 19.0 (17.8 to 20.4) | 18.9 (17.6 to 20.2) |
| NDCMC | 3.9 (3.3 to 4.6) | 4.5 (3.8 to 5.2) |
Local reactions included redness, swelling, and pain at injection site and were recorded in electronic diary (e-diary). Redness and swelling were measured and recorded in measuring device units. 1 measuring device unit= 0.5 centimetre (cm). Redness and swelling were graded as mild (\>2.0 to 5.0 cm), moderate (\>5.0 to 10.0 cm), severe (\>10.0 cm) and grade 4 (necrosis or exfoliative dermatitis for redness and necrosis for swelling). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization for the severe pain at the injection site). Grade 4 reactions were classified by the investigator or medically qualified person.
| Percentage of participants | Maternal Participants: RSVpreF | Maternal Participants: Placebo |
|---|---|---|
| Redness: Any | 7.2 (6.4 to 8.1) | 0.2 (0.1 to 0.4) |
| Redness: Mild | 5.0 (4.3 to 5.7) | 0.1 (0.0 to 0.3) |
| Redness: Moderate | 2.1 (1.7 to 2.6) | 0.1 (0.0 to 0.3) |
| Redness: Severe | 0.1 (0.0 to 0.3) | 0 (0.0 to 0.1) |
| Redness: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Swelling: Any | 6.2 (5.4 to 7.0) | 0.2 (0.1 to 0.4) |
| Swelling: Mild | 4.1 (3.5 to 4.8) | 0.1 (0.0 to 0.3) |
| Swelling: Moderate | 2.0 (1.6 to 2.5) | 0.1 (0.0 to 0.2) |
| Swelling: Severe | 0.1 (0.0 to 0.2) | 0 (0.0 to 0.1) |
| Swelling: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Pain at injection site: Any | 40.7 (39.1 to 42.3) | 10.2 (9.2 to 11.2) |
| Pain at injection site: Mild | 36.1 (34.6 to 37.7) | 9.3 (8.4 to 10.3) |
| Pain at injection site: Moderate | 4.5 (3.8 to 5.2) | 0.9 (0.6 to 1.2) |
| Pain at injection site: Severe | 0.1 (0.0 to 0.3) | 0 (0.0 to 0.1) |
| Pain at injection site: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
Systemic events included: fever, fatigue, headache, nausea, muscle pain, joint pain, vomiting and diarrhea and were recorded by participants in an e-diary. Fever was defined as an oral temperature \>=38.0 degree Celsius \[C\]) and classified as mild (38.0 to 38.4), moderate (38.5 to 38.9), severe (39.0 to 40.0) and grade 4 (\>40.0 degree C). Headache, nausea, fatigue, muscle pain and joint pain were graded as mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily activity). Vomiting: mild (1-2 times in 24 hours \[H\]), moderate (\>2 times in 24 H), severe (required intravenous \[IV\] hydration). Diarrhea: mild (2-3 loose stools in 24 H), moderate (4-5 loose stools in 24 H), severe (\>=6 in 24 H). For all systemic events except fever, Grade 4= emergency room visit or hospitalization. Grade 4 events were classified by investigator or medically qualified person.
| Percentage of participants | Maternal Participants: RSVpreF | Maternal Participants: Placebo |
|---|---|---|
| Fever: >=38.0 degree C | 2.6 (2.1 to 3.1) | 2.9 (2.4 to 3.5) |
| Fever: 38.0 to 38.4 degree C | 1.7 (1.3 to 2.1) | 1.5 (1.1 to 2.0) |
| Fever: 38.5 to 38.9 degree C | 0.8 (0.5 to 1.1) | 1.2 (0.8 to 1.6) |
| Fever: 39.0 to 40.0 degree C | 0.1 (0.0 to 0.2) | 0.1 (0.0 to 0.3) |
| Fever: >40.0 degree C | 0.1 (0.0 to 0.2) | 0.1 (0.0 to 0.3) |
| Fatigue: Any | 46.1 (44.5 to 47.7) | 43.8 (42.2 to 45.4) |
| Fatigue: Mild | 23.5 (22.1 to 24.9) | 22.7 (21.4 to 24.1) |
| Fatigue: Moderate | 21.3 (20.0 to 22.7) | 19.6 (18.4 to 21.0) |
| Fatigue: Severe | 1.3 (1.0 to 1.8) | 1.4 (1.1 to 1.9) |
| Fatigue: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Headache: Any | 31.0 (29.5 to 32.5) | 27.6 (26.2 to 29.1) |
| Headache: Mild | 20.2 (18.9 to 21.5) | 17.9 (16.7 to 19.2) |
| Headache: Moderate | 10.4 (9.4 to 11.4) | 9.4 (8.5 to 10.4) |
| Headache: Severe | 0.4 (0.2 to 0.7) | 0.4 (0.2 to 0.6) |
| Headache: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Nausea: Any | 20.0 (18.7 to 21.3) | 19.3 (18.0 to 20.6) |
| Nausea: Mild | 14.4 (13.3 to 15.6) | 13.9 (12.8 to 15.0) |
| Nausea: Moderate | 5.4 (4.7 to 6.1) | 5.2 (4.5 to 6.0) |
| Nausea: Severe | 0.2 (0.1 to 0.4) | 0.2 (0.1 to 0.4) |
| Nausea: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Muscle pain: Any | 26.6 (25.1 to 28.0) | 17.1 (15.9 to 18.4) |
| Muscle pain: Mild | 17.6 (16.4 to 18.9) | 10.0 (9.0 to 11.0) |
| Muscle pain: Moderate | 8.6 (7.7 to 9.5) | 6.8 (6.0 to 7.7) |
| Muscle pain: Severe | 0.4 (0.2 to 0.6) | 0.3 (0.2 to 0.6) |
| Muscle pain: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Joint pain: Any | 11.6 (10.6 to 12.7) | 10.5 (9.5 to 11.6) |
| Joint pain: Mild | 6.5 (5.7 to 7.3) | 6.0 (5.2 to 6.8) |
| Joint pain: Moderate | 4.9 (4.2 to 5.7) | 4.4 (3.8 to 5.2) |
| Joint pain: Severe | 0.2 (0.1 to 0.4) | 0.1 (0.0 to 0.2) |
| Joint pain: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Vomiting: Any | 7.9 (7.0 to 8.8) | 7.0 (6.2 to 7.8) |
| Vomiting: Mild | 6.4 (5.6 to 7.2) | 5.4 (4.7 to 6.1) |
| Vomiting: Moderate | 1.3 (0.9 to 1.7) | 1.5 (1.2 to 2.0) |
| Vomiting: Severe | 0.2 (0.1 to 0.4) | 0.1 (0.0 to 0.2) |
| Vomiting: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
| Diarrhea: Any | 11.3 (10.3 to 12.3) | 11.4 (10.4 to 12.5) |
| Diarrhea: Mild | 9.1 (8.2 to 10.1) | 9.4 (8.4 to 10.4) |
| Diarrhea: Moderate | 2.0 (1.6 to 2.5) | 1.9 (1.4 to 2.4) |
| Diarrhea: Severe | 0.1 (0.0 to 0.3) | 0.2 (0.1 to 0.4) |
| Diarrhea: Grade 4 | 0 (0.0 to 0.1) | 0 (0.0 to 0.1) |
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were included in this outcome measure.
| Percentage of participants | Maternal Participants: RSVpreF | Maternal Participants: Placebo |
|---|---|---|
| Percentage of Maternal Participants With AEs From the Time of Vaccination Through 1 Month After Vaccination (Safety) | 14.0 (12.9 to 15.1) | 13.2 (12.2 to 14.4) |
An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect or that was considered an important medical event.
| Percentage of participants | Maternal Participants: RSVpreF | Maternal Participants: Placebo |
|---|---|---|
| Percentage of Maternal Participants With SAEs Throughout the Study Period (Safety) | 16.6 (15.4 to 17.8) | 15.8 (14.6 to 17.0) |
Results are reported as confirmed by endpoint adjudication committee.
| %participants with hospitalization cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| 90 days after birth | 0.3 | 0.9 |
| 120 days after birth | 0.4 | 1.1 |
| 150 days after birth | 0.5 | 1.2 |
| 180 days after birth | 0.6 | 1.3 |
| 360 days after birth | 1.4 | 1.9 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| 90 days after birth | 5.6 | 6.2 |
| 120 days after birth | 8.1 | 8.8 |
| 150 days after birth | 10.3 | 11.3 |
| 180 days after birth | 12.4 | 13.0 |
| 360 days after birth | 17.5 | 18.4 |
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.
| % of participants with MA-LRTI cases | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|
| 210 days after birth | 2.3 | 4.0 |
| 240 days after birth | 2.5 | 4.2 |
| 270 days after birth | 2.8 | 4.4 |
| 360 days after birth | 3.4 | 5.1 |
Collected over Maternal participants: Local reactions and systemic events: From Day 1 to Day 7 after vaccination; SAEs: From vaccination on Day 1 up to 6 months after delivery (maximum up to 10 months); Non-SAEs: From vaccination on Day 1 up to 1 month after vaccination; Infant participants: SAEs: From birth up to 24 months of age; Non-SAEs: From birth up to 1 month after birth. Non-serious events are listed at a 1% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Maternal Participants: RSVpreF | 1/3,698 (0%) | 613/3,698 (16.6%) | 2,755/3,698 (74.5%) |
| Maternal Participants: Placebo | 0/3,687 (0%) | 581/3,687 (15.8%) | 2,339/3,687 (63.4%) |
| Infant Participants: RSVpreF | 8/3,659 (0.2%) | 697/3,659 (19%) | 674/3,659 (18.4%) |
| Infant Participants: Placebo | 14/3,646 (0.4%) | 689/3,646 (18.9%) | 598/3,646 (16.4%) |
| Event | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|---|---|
| Jaundice neonatalPregnancy, puerperium and perinatal conditions | 0/3698 | 0/3687 | 77/3659 | 69/3646 |
| Foetal distress syndromePregnancy, puerperium and perinatal conditions | 67/3698 | 65/3687 | 1/3659 | 0/3646 |
| Pre-eclampsiaPregnancy, puerperium and perinatal conditions | 67/3698 | 53/3687 | 0/3659 | 0/3646 |
| Hyperbilirubinaemia neonatalHepatobiliary disorders | 0/3698 | 0/3687 | 51/3659 | 42/3646 |
| Premature babyPregnancy, puerperium and perinatal conditions | 0/3698 | 0/3687 | 49/3659 | 42/3646 |
| Respiratory distressRespiratory, thoracic and mediastinal disorders | 0/3698 | 0/3687 | 49/3659 | 46/3646 |
| Atrial septal defectCongenital, familial and genetic disorders | 0/3698 | 0/3687 | 37/3659 | 46/3646 |
| Arrested labourPregnancy, puerperium and perinatal conditions | 37/3698 | 43/3687 | 0/3659 | 0/3646 |
| Gestational hypertensionPregnancy, puerperium and perinatal conditions | 43/3698 | 41/3687 | 0/3659 | 0/3646 |
| Nonreassuring foetal heart rate patternCardiac disorders | 37/3698 | 30/3687 | 0/3659 | 0/3646 |
| Event | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo |
|---|---|---|---|---|
| Fatigue (FATIGUE)General disorders | 1696/3678 | 1599/3651 | 0/3659 | 0/3646 |
| Injection site pain (PAIN AT INJECTION SITE)General disorders | 1496/3678 | 371/3651 | 0/3659 | 0/3646 |
| Headache (HEADACHE)Nervous system disorders | 1141/3678 | 1009/3651 | 0/3659 | 0/3646 |
| Myalgia (MUSCLE PAIN)Musculoskeletal and connective tissue disorders | 977/3678 | 626/3651 | 0/3659 | 0/3646 |
| Nausea (NAUSEA)Gastrointestinal disorders | 734/3678 | 705/3651 | 0/3659 | 0/3646 |
| Arthralgia (JOINT PAIN)Musculoskeletal and connective tissue disorders | 426/3678 | 384/3651 | 0/3659 | 0/3646 |
| Diarrhoea (DIARRHEA)Gastrointestinal disorders | 414/3678 | 416/3651 | 0/3569 | 0/3646 |
| Vomiting (VOMITING)Gastrointestinal disorders | 289/3678 | 254/3651 | 0/3659 | 0/3646 |
| Erythema (REDNESS)Skin and subcutaneous tissue disorders | 265/3678 | 8/3651 | 0/3659 | 0/3646 |
| Swelling (SWELLING)General disorders | 228/3678 | 8/3651 | 0/3659 | 0/3646 |
Maternal safety population included all randomized maternal participants who received investigational product. Infant safety population included all infant participants who were born to vaccinated maternal participants.
| Age, Categorical(Participants) | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo | Total |
|---|---|---|---|---|---|
| <=18 years | 9 | 9 | 3659 | 3646 | 7323 |
| Between 18 and 65 years | 3689 | 3678 | 0 | 0 | 7367 |
| >=65 years | 0 | 0 | 0 | 0 | 0 |
| Sex: Female, Male(Participants) | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo | Total |
|---|---|---|---|---|---|
| Female | 3698 | 3687 | 1794 | 1815 | 10994 |
| Male | 0 | 0 | 1865 | 1831 | 3696 |
| Ethnicity (NIH/OMB)(Participants) | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo | Total |
|---|---|---|---|---|---|
| Hispanic or Latino | 1063 | 1086 | 1079 | 1081 | 4309 |
| Not Hispanic or Latino | 2605 | 2568 | 2529 | 2519 | 10221 |
| Unknown or Not Reported | 30 | 33 | 51 | 46 | 160 |
| Race (NIH/OMB)(Participants) | Maternal Participants: RSVpreF | Maternal Participants: Placebo | Infant Participants: RSVpreF | Infant Participants: Placebo | Total |
|---|---|---|---|---|---|
| American Indian or Alaska Native | 38 | 37 | 42 | 36 | 153 |
| Asian | 456 | 464 | 446 | 456 | 1822 |
| Native Hawaiian or Other Pacific Islander | 9 | 12 | 13 | 11 | 45 |
| Black or African American | 720 | 725 | 706 | 706 | 2857 |
| White | 2397 | 2375 | 2340 | 2328 | 9440 |
| More than one race | 30 | 21 | 65 | 59 | 175 |
| Unknown or Not Reported | 48 | 53 | 47 | 50 | 198 |
Showing the first 100 of 464 sites across 18 countries. Choose a country and city above to see the rest.
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
Data sharing details ↗ · www.pfizer.com
Ran from Jun 2020 to primary completion in Oct 2023, 40 months.
Results were first posted in Feb 2025, 1 year 3 months after primary completion.
Of 41 phase 3 interventional studies under Respiratory Tract Infections, half reached primary completion within 15 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 73. This study's 40 months is above that.
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Studies of the drug tested here: Abrysvo
Respiratory Tract Infections →