# RSV vaccination in pregnancy to protect the infant Intervention · id `maternal:maternal-rsv-vaccination` · Maternal & Newborn Atlas · release `c7fb95f1d15a7d13` (public) > General information from published sources, not medical advice, and not reviewed by clinicians. Check the cited source before relying on anything here. The atlas's own text and curation may be reused under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0, https://creativecommons.org/licenses/by-nc/4.0/): credit the atlas, and do not use it commercially. See the atlas About page. Text quoted from a source stays under that source's own terms, given as the source's reuse\_basis. The atlas's reuse terms do not cover it. The downloads list each quotation with its source in third\_party\_quotations. Browse, life stage: Pregnancy; Infant follow-up Browse, care area: The baby's first year ## In plain language A single RSV vaccine injection given to a pregnant person so that her baby is protected from serious RSV lung illness after birth. In the MATISSE trial the vaccine lowered severe RSV illness in babies in the first 90 and 180 days after birth; it did not meet the trial's statistical success criterion for RSV illness of any severity at 90 days. In the United States the vaccine is approved for use at 32 through 36 weeks of pregnancy, and the regulator reported a numerical imbalance in preterm births that it could neither link to the vaccine nor rule out. ## Technical summary The vaccine is given to the mother and the outcomes are measured in her infant, so the claims use separate maternal and infant contexts. MATISSE (NCT04424316) randomised women at 24 through 36 weeks to the vaccine or placebo; the interim analysis met the success criterion for one of two primary end points. The licensed window is 32 through 36 weeks. The trial's safety summary reports no safety signals; the regulator's description of the licensed product reports numerical imbalances in pre-eclampsia and preterm births, with postmarketing studies required. The licensed product has its own page. MedlinePlus lists the vaccine as available between 32 and 36 weeks of pregnancy. ## Claims, with the population each applies to ## Context: Infants born to women who received RSVpreF or placebo in pregnancy, followed to 180 days after birth (MATISSE) Recipient: Newborn; Population: Infants of the women randomised in MATISSE. The 24 to 36 week window is the mother's gestational age at vaccination; it is not a limit on the infant's gestational age at birth, which the abstract does not restrict. The abstract evaluated 3570 infants of vaccinated women and 3558 infants of placebo recipients.; Care setting: Prenatal and paediatric care settings in 18 countries (international, placebo-controlled trial).; Geography: 18 countries listed in ClinicalTrials.gov (see the MATISSE study page); Life stage: Infants from birth, with RSV illness counted within 90, 120, 150 and 180 days after birth; Gestational age: Not reported; Postnatal age: Not reported; Follow-up: RSV-associated illness within 90, 120, 150 and 180 days after birth; safety follow-up of infants and toddlers up to 24 months of age (abstract). ### In MATISSE, medically attended RSV-associated lower respiratory tract illness of any severity within 90 days after birth occurred in 24 infants of women in the vaccine group and 56 infants of women in the placebo group (vaccine efficacy 57.1%; 99.5% confidence interval 14.7 to 79.8). The authors state that these results did not meet the statistical success criterion. - Category: Effect - Evidence stage: Interventional - Certainty: Certainty not assessed - Applies to: Recipient: Newborn; Population: Infants of the women randomised in MATISSE. The 24 to 36 week window is the mother's gestational age at vaccination; it is not a limit on the infant's gestational age at birth, which the abstract does not restrict. The abstract evaluated 3570 infants of vaccinated women and 3558 infants of placebo recipients.; Care setting: Prenatal and paediatric care settings in 18 countries (international, placebo-controlled trial).; Geography: 18 countries listed in ClinicalTrials.gov (see the MATISSE study page); Life stage: Infants from birth, with RSV illness counted within 90, 120, 150 and 180 days after birth; Gestational age: Not reported; Postnatal age: Not reported; Follow-up: RSV-associated illness within 90, 120, 150 and 180 days after birth; safety follow-up of infants and toddlers up to 24 months of age (abstract). - Limitations: Only the PubMed abstract was read; the full text was not. This is one of the trial's two primary end points, reported at the interim analysis, and the statistical success criterion was not met for it. The abstract does not say whether later analyses changed this result. The trial was funded by Pfizer. - Last checked: 2026-10-15 - Sources: 1. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 2, fragment 1 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 2. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 2, fragment 2 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 3. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 4, fragment 1 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 4. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 4, fragment 2 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 5. Background: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 3, fragment 1 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract (context for the claim). 6. Background: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 3, fragment 2 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract (context for the claim). ### In MATISSE, the authors reported that no safety signals were detected in infants and toddlers up to 24 months of age. Adverse events reported within 1 month after birth were similar in the vaccine group and the placebo group: 37.1% of infants of vaccinated women and 34.5% of infants of placebo recipients. - Category: Safety - Evidence stage: Interventional - Certainty: Certainty not assessed - Applies to: Recipient: Newborn; Population: Infants of the women randomised in MATISSE. The 24 to 36 week window is the mother's gestational age at vaccination; it is not a limit on the infant's gestational age at birth, which the abstract does not restrict. The abstract evaluated 3570 infants of vaccinated women and 3558 infants of placebo recipients.; Care setting: Prenatal and paediatric care settings in 18 countries (international, placebo-controlled trial).; Geography: 18 countries listed in ClinicalTrials.gov (see the MATISSE study page); Life stage: Infants from birth, with RSV illness counted within 90, 120, 150 and 180 days after birth; Gestational age: Not reported; Postnatal age: Not reported; Follow-up: RSV-associated illness within 90, 120, 150 and 180 days after birth; safety follow-up of infants and toddlers up to 24 months of age (abstract). - Limitations: Only the PubMed abstract was read; the full text was not. The abstract gives these figures in one sentence for women and infants together, in the order women then infants; the pairing of 37.1% and 34.5% with infants follows that order. The abstract does not give the types of events, and it does not report preterm birth, low birth weight or jaundice, which FDA reported as imbalances in its description of the safety studies of the licensed vaccine. - Last checked: 2026-10-15 - Sources: 1. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 5. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 2. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 6, fragment 1 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 3. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 6, fragment 2 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 4. Background: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract (context for the claim). ### In the phase 3, double-blind MATISSE trial, pregnant women at 24 through 36 weeks' gestation were randomly assigned 1:1 to a single intramuscular injection of 120 micrograms of a bivalent RSV prefusion F protein vaccine (RSVpreF) or placebo. At a prespecified interim analysis the success criterion was met for one primary end point. Medically attended severe RSV-associated lower respiratory tract illness within 90 days after birth occurred in 6 infants of women in the vaccine group and 33 infants of women in the placebo group (vaccine efficacy 81.8%; 99.5% confidence interval 40.6 to 96.3); 19 cases and 62 cases, respectively, occurred within 180 days after birth (vaccine efficacy 69.4%; 97.58% confidence interval 44.3 to 84.1). - Category: Effect - Evidence stage: Interventional - Certainty: Certainty not assessed - Applies to: Recipient: Newborn; Population: Infants of the women randomised in MATISSE. The 24 to 36 week window is the mother's gestational age at vaccination; it is not a limit on the infant's gestational age at birth, which the abstract does not restrict. The abstract evaluated 3570 infants of vaccinated women and 3558 infants of placebo recipients.; Care setting: Prenatal and paediatric care settings in 18 countries (international, placebo-controlled trial).; Geography: 18 countries listed in ClinicalTrials.gov (see the MATISSE study page); Life stage: Infants from birth, with RSV illness counted within 90, 120, 150 and 180 days after birth; Gestational age: Not reported; Postnatal age: Not reported; Follow-up: RSV-associated illness within 90, 120, 150 and 180 days after birth; safety follow-up of infants and toddlers up to 24 months of age (abstract). - Limitations: Only the PubMed abstract was read; the full text was not. The result is from an interim analysis, and only one of the two primary end points met the statistical success criterion (see the separate claim on illness of any severity). The abstract gives 99.5% intervals at 90 days and 97.58% intervals at later time points. Women were vaccinated at 24 through 36 weeks in the trial, a wider window than the 32 through 36 weeks FDA approved. The trial was funded by Pfizer. - Last checked: 2026-10-15 - Sources: 1. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 1, fragment 1 of 3. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 2. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 1, fragment 2 of 3. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 3. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, METHODS, sentence 1, fragment 3 of 3. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 4. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 1. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 5. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 3, fragment 1 of 3. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 6. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 3, fragment 2 of 3. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 7. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 3, fragment 3 of 3. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 8. Background: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, CONCLUSIONS, sentence 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract (context for the claim). ## Context: Healthy pregnant women at 24 to 36 weeks vaccinated with RSVpreF or placebo (MATISSE) Recipient: Maternal; Population: Healthy women aged 49 years or younger with an uncomplicated singleton pregnancy at no known increased risk of complications, between 24 0/7 and 36 0/7 weeks of gestation on the day of planned vaccination, who each received one injection of RSVpreF vaccine or placebo.; Care setting: Prenatal care settings in 18 countries (international, placebo-controlled trial).; Geography: Argentina, Australia, Brazil, Canada, Chile, Denmark, Finland, Japan, Mexico, the Netherlands, New Zealand, the Philippines, South Africa, South Korea, Spain, Taiwan, The Gambia and the United States (ClinicalTrials.gov locations); Life stage: Pregnancy, from vaccination to birth and the safety follow-up after injection; Gestational age: 24 weeks 0 days (168 days) to 36 weeks 0 days (252 days), measured at enrolment; Postnatal age: Not reported; Follow-up: Adverse events within 1 month after injection (abstract); the registry lists longer maternal safety outcomes. ### In MATISSE, the authors reported that no safety signals were detected in maternal participants. Adverse events reported within 1 month after injection or within 1 month after birth were similar in the vaccine group and the placebo group: 13.8% of women in the vaccine group and 13.1% of women in the placebo group. - Category: Safety - Evidence stage: Interventional - Certainty: Certainty not assessed - Applies to: Recipient: Maternal; Population: Healthy women aged 49 years or younger with an uncomplicated singleton pregnancy at no known increased risk of complications, between 24 0/7 and 36 0/7 weeks of gestation on the day of planned vaccination, who each received one injection of RSVpreF vaccine or placebo.; Care setting: Prenatal care settings in 18 countries (international, placebo-controlled trial).; Geography: Argentina, Australia, Brazil, Canada, Chile, Denmark, Finland, Japan, Mexico, the Netherlands, New Zealand, the Philippines, South Africa, South Korea, Spain, Taiwan, The Gambia and the United States (ClinicalTrials.gov locations); Life stage: Pregnancy, from vaccination to birth and the safety follow-up after injection; Gestational age: 24 weeks 0 days (168 days) to 36 weeks 0 days (252 days), measured at enrolment; Postnatal age: Not reported; Follow-up: Adverse events within 1 month after injection (abstract); the registry lists longer maternal safety outcomes. - Limitations: Only the PubMed abstract was read; the full text was not. The abstract gives these figures in one sentence for women and infants together, in the order women then infants; the pairing of 13.8% and 13.1% with women follows that order. The abstract does not break the women's adverse events down by type, and it does not report pre-eclampsia or preterm birth; FDA's description of the safety studies of the licensed vaccine, which reports numerical imbalances in both, is on the Abrysvo page. - Last checked: 2026-10-15 - Sources: 1. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 5. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 2. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 6, fragment 1 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 3. Supports: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 6, fragment 2 of 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract. 4. Background: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, RESULTS, sentence 2. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract (context for the claim). 5. Background: Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities. The full text and the version of record were not fetched.) Locator: Abstract, CONCLUSIONS, sentence 1. Retrieved 2026-10-15T13:48:54Z. Source state: Current. Snapshot hash: 0c20a3db223731033cecc187e895c1b4bebdc724eb28c58a4e8873b90bf72892. How it applies: PubMed abstract (context for the claim). 6. Background: A Trial to Evaluate the Efficacy and Safety of RSVpreF in Infants Born to Women Vaccinated During Pregnancy. (Registry, edition ClinicalTrials.gov API v2 record, last update posted 2025-02-11.) Locator: protocolSection.eligibilityModule.eligibilityCriteria. Retrieved 2026-10-15T13:48:52Z. Source state: Current. Snapshot hash: dd4a074aad5cabb6dcae2a3f0a8063d20590ff9ea27e40700fdbb1520537b632. How it applies: ClinicalTrials.gov record (context for the claim). ## Connected pages - MATISSE: efficacy against severe RSV illness in infants at 90 and 180 days after birth: RSV lower respiratory tract disease in infants (`maternal:infant-rsv-disease`) [a claim, not a settled fact; see claim `maternal:claim-matisse-severe-rsv-lrti-efficacy` and its context] - MATISSE: illness of any severity within 90 days after birth did not meet the success criterion: RSV lower respiratory tract disease in infants (`maternal:infant-rsv-disease`) [a claim, not a settled fact; see claim `maternal:claim-matisse-any-rsv-lrti-90-days` and its context] - The licensed product: Abrysvo (RSV vaccine, Pfizer) (`maternal:abrysvo`) - Filed under this front: Medicines and vaccines (`maternal:front-medicines-and-vaccines`) - Investigated in: MATISSE trial (maternal RSV vaccine, infant outcomes) (`maternal:matisse-trial`) ## Provenance Content hash: 668cc6057e1197d1a3de9e7021fa5e7c59cfceb0da85617c8d82f73faba4a89a Last substantive edit: 2026-10-15 Evidence last checked: 2026-10-15