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# CDC Recommends Maternal RSV Vaccine at 32–36 Weeks After 11-1 Vote, Adding Second Infant Protection Option
- URL: https://www.theamericanquorum.com/taq-historical-2023-09-23-healthcare/
- Published: 2023-09-24T03:59:00.000Z
- Updated: 2023-09-24T03:59:00.000Z
- Description: CDC recommended Pfizer’s Abrysvo during weeks 32–36 of pregnancy, using seasonal administration, giving families a maternal-vaccine alternative to infant nirsevimab for RSV prevention.
- Author: Kenneth R. Deans Jr.
- Tags: Healthcare, #Import 2026-09-01 05:59

The Centers for Disease Control and Prevention on Friday recommended Pfizer’s Abrysvo respiratory syncytial virus vaccine for pregnant people at 32 through 36 weeks of gestation during RSV season, creating a second pathway for protecting newborns from a virus that is the leading cause of hospitalization among U.S. infants.

The [CDC recommendation](https://www.cdc.gov/media/releases/2023/p0922-RSV-maternal-vaccine.html?ref=theamericanquorum.com) followed an 11-1 vote by the Advisory Committee on Immunization Practices. The agency recommends a single maternal dose during weeks 32 through 36, generally from September through January in most of the continental United States, so antibodies generated by the pregnant patient can cross the placenta and protect the infant during the first months of life.

## The recommendation follows the first FDA approval of an RSV vaccine during pregnancy

The Food and Drug Administration [approved Abrysvo for maternal use](https://www.fda.gov/news-events/press-announcements/fda-approves-first-vaccine-pregnant-individuals-prevent-rsv-infants?ref=theamericanquorum.com) on August 21, making it the first vaccine in the United States authorized specifically to prevent RSV lower respiratory tract disease in infants through vaccination during pregnancy. The indication covers administration at 32 through 36 weeks of gestation and protection from birth through 6 months of age.

In the pivotal trial cited by FDA, vaccination reduced severe RSV lower respiratory tract disease by 81.8% during the first 90 days after birth and 69.4% through 180 days in the overall efficacy population. In the subgroup vaccinated at 32 through 36 weeks—the interval ultimately approved by FDA—the estimated reduction in severe disease was 91.1% through 90 days and 76.5% through 180 days.

Pfizer’s [August approval announcement](https://www.pfizer.com/news/press-release/press-release-detail/us-fda-approves-abrysvotm-pfizers-vaccine-prevention-0?ref=theamericanquorum.com) said the maternal indication was supported by the Phase 3 MATISSE study involving more than 7,000 pregnant participants and their infants. Abrysvo contains prefusion F proteins representing RSV A and B strains and is administered as a single intramuscular dose.

## The clinical trial showed strong protection against severe disease

The MATISSE trial results were published in April in the [New England Journal of Medicine](https://www.nejm.org/doi/abs/10.1056/nejmoa2216480?ref=theamericanquorum.com). Investigators reported that maternal vaccination substantially reduced medically attended severe RSV-associated lower respiratory tract illness in infants. The study was randomized and placebo-controlled and followed infants after birth to assess both efficacy and safety.

The trial is registered as [NCT04424316](https://clinicaltrials.gov/study/NCT04424316?ref=theamericanquorum.com), providing the protocol framework, eligibility criteria and prespecified endpoints used to evaluate maternal immunization. The program reflects a different preventive mechanism from vaccinating the infant directly: the mother generates RSV-neutralizing antibodies, which are transferred before delivery and provide passive protection during the period when very young infants face their highest hospitalization risk.

Safety was a major part of the federal review. FDA noted a numerical imbalance in preterm births—5.7% among vaccine recipients versus 4.7% among placebo recipients—and said available data were insufficient to establish or exclude a causal relationship. The approved 32-to-36-week window is intended in part to reduce concern about preterm delivery associated with vaccination earlier in pregnancy. FDA is requiring postmarketing studies addressing preterm birth and hypertensive disorders of pregnancy.

## Families now have two new ways to protect most infants

The maternal vaccine enters practice alongside nirsevimab, a long-acting monoclonal antibody approved in July for infants and certain young children. FDA’s [Beyfortus approval](https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-prevent-rsv-babies-and-toddlers?ref=theamericanquorum.com) covers newborns and infants born during or entering their first RSV season, as well as some children up to 24 months who remain vulnerable during a second season.

CDC’s August [nirsevimab recommendation](https://www.cdc.gov/mmwr/volumes/72/wr/mm7234a4.htm?ref=theamericanquorum.com) advises one dose for infants younger than 8 months entering their first season and for certain high-risk children 8 through 19 months entering a second season. With Friday’s maternal recommendation, clinicians can now protect most infants either through vaccination during pregnancy or through nirsevimab after birth.

CDC says most infants will not need both. The choice can depend on timing, maternal vaccination status, product availability and clinical circumstances. If an infant is born less than two weeks after maternal vaccination, for example, clinicians may consider nirsevimab because there may not have been enough time for adequate maternal antibody transfer.

## Seasonal timing is designed to concentrate protection when RSV circulates

RSV activity typically rises during fall and winter in much of the continental United States, although seasonality differs in Alaska, tropical areas and some other jurisdictions. CDC’s recommendation therefore combines a gestational window with a seasonal window: vaccination during 32 through 36 weeks, generally from September through January.

The timing is intended to align peak infant antibody levels with the months of greatest RSV exposure. It also makes implementation more complex than a simple year-round vaccination recommendation. Obstetric practices will need to identify eligible pregnancies based on both gestational age and calendar timing, document vaccination in records accessible to pediatric clinicians and explain to families whether the infant is expected to need nirsevimab after birth.

Pfizer welcomed the ACIP vote in a [September 22 statement](https://www.pfizer.com/news/press-release/press-release-detail/pfizer-broadens-portfolio-respiratory-vaccines-recommended?ref=theamericanquorum.com), describing maternal immunization as an additional element in its respiratory-vaccine portfolio. The vaccine had already been approved earlier this year for adults 60 and older under shared clinical decision-making, but the maternal indication serves a distinct public-health objective: protecting infants before they can mount their own vaccine response.

## RSV prevention is changing rapidly after decades with few options

For years, prevention for infants was largely limited to palivizumab, a monoclonal antibody reserved for relatively small groups of high-risk children and requiring repeated doses during RSV season. In a matter of months, federal regulators have now cleared nirsevimab for broad infant use and a maternal vaccine designed to protect infants through transferred antibodies.

That changes the clinical conversation from whether RSV prevention is available to which preventive route is most appropriate. Health systems must coordinate obstetric, newborn and pediatric care so that infants are protected without unnecessary duplication. Payers and federal programs must also determine coverage and distribution as both products enter their first full U.S. RSV season.

Friday’s recommendation is therefore a significant expansion of routine respiratory prevention. For the first time, a pregnant patient can receive an RSV vaccine late in pregnancy specifically to protect the infant after birth. Together with nirsevimab, that gives clinicians two complementary tools against a virus that sends tens of thousands of U.S. children to hospitals each year and has historically been especially difficult to prevent in the youngest patients.