The RSV vaccine given in the last weeks of pregnancy cut a newborn's risk of an RSV-related hospital stay by 51 to 70 percent through the first respiratory season, and cut infant RSV illness overall by 74 percent, a new evidence review in JAMA found.
The review was published on September 2, 2026, by the American Medical Association and the University of Minnesota's Vaccine Integrity Project.
RSV, short for respiratory syncytial virus, is the leading cause of hospital admission for babies in their first year.
The vaccine is given between 32 and 36 weeks of pregnancy, so the mother passes protective antibodies to the baby before birth.
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When to get the shot, and why timing matters
The recommendation is to vaccinate pregnant women between September and the end of February, so the baby is covered through the peak RSV months.
If a mother did not get the shot during pregnancy, infants younger than 8 months entering their first RSV season should get a preventive antibody injection, called nirsevimab, instead.
The JAMA reviewers pulled together randomized trials and real-world studies, including data on thousands of infants born to vaccinated mothers.
The 51 percent figure for hospital admission within 120 days of birth comes from a post hoc analysis of a randomized trial and had a wide confidence interval.
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The 70 percent figure, from an observational US study across the first respiratory season, was more precise. The 74 percent figure was for broader RSV illness in babies.
Who else the shot is for
The same review found the RSV shot cut hospital admissions in older adults meaningfully in the first season, though protection dropped over 12 to 18 months.
Medical groups recommend a one-time RSV shot for adults 75 and older, and for adults 50 to 74 who are at increased risk from conditions like heart or lung disease.
For RSV in babies, more children may now qualify for the RSV vaccine under updated guidelines than in earlier seasons, including some infants entering their second RSV season with certain health conditions.
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The flu and COVID picture for this fall
The RSV review came out alongside separate JAMA reviews of the flu and COVID vaccines, all conducted by the same AMA and Vaccine Integrity Project team.
The flu shot is recommended for everyone 6 months and older, ideally before the end of October, according to the medical societies backing the reviews.
The COVID guidance from the medical groups is broader than the federal guidance issued in August 2026. It recommends a COVID shot for everyone 19 and older, and for children 6 months to 18 years based on risk factors, including those who are pregnant, planning a pregnancy or nursing.
This wider stance is why doctors released their own fall vaccine guidelines this year.
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According to the review team, led by co-lead Nicole Basta, PhD, RSV vaccination of older adults and pregnant women, together with infant immunization using monoclonal antibodies, substantially reduced severe illness and hospitalization.
The reviewers reported no new safety concerns for maternal RSV vaccination. None of the comparative studies found a link between the shot and preterm birth or other adverse pregnancy outcomes.
Anyone pregnant this fall can ask their obstetrician whether they fall inside the 32 to 36 week window before the end of February.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.