RSV Vaccine Shows Similar Safety in Pregnancy
Pregnant people in the U.S. saw similar maternal and infant safety outcomes with vaccination across two RSV seasons.
Updated on Nov. 4, 2026 in Pregnancy
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Interim U.S. data found similar maternal and infant safety outcomes for vaccinated and unvaccinated pregnancies across two RSV seasons. Vaccinated pregnancies also showed a slightly lower rate of preterm birth, a finding relevant to expectant parents across the country.
Why it matters
Pregnant people weigh vaccine decisions carefully, and early safety data from a large real-world sample helps inform those conversations. The analysis was released now as an interim look ahead of a final, more detailed evaluation.
This interim observational study matched vaccinated and unvaccinated pregnancies from five U.S. health plans recorded between Sept. 22, 2023, and Aug. 14, 2025. Across 131,567 eligible live-birth pregnancies, preterm birth was 4.7% in vaccinated pregnancies versus 6.3% in unvaccinated ones, while hypertensive disorders were 16.8% versus 15.8%.
The players
IDWeek
An annual infectious disease conference where clinicians and researchers present new findings on infection prevention, vaccines, and treatment.
The details
Researchers paired each vaccinated pregnancy with an unvaccinated one using matching criteria including health plan, gestational age, year and quarter of pregnancy start, evidence of immunocompromise or hypertensive disorders, and a propensity score that estimates the likelihood of vaccination. This matching helps make the two groups more comparable, so differences in outcomes are less likely to reflect pre-existing differences between the people involved. Outcomes compared between the matched groups included pregnancy, maternal, and infant measures, with preterm birth and pregnancy-associated hypertensive disorders highlighted in the findings.
Timeline
Vaccinated pregnancies were identified between Sept. 22, 2023, and Aug. 14, 2025.
The interim data was presented at IDWeek on Nov. 4, 2026.
Health Landscape
Maternal RSV vaccination has been studied across multiple U.S. seasons as a way to protect newborns during their first months, when RSV can be severe. This interim analysis adds real-world safety data from health plan records to that growing body of evidence, while the final analysis is still pending.
If you are pregnant or planning pregnancy, this interim data is worth discussing with your obstetric clinician as you consider RSV vaccination in the context of your own health history. The population-level finding does not replace a personal conversation about timing and risk.
The takeaway
Interim data showed similar safety outcomes for vaccinated and unvaccinated pregnancies, with slightly lower preterm birth in the vaccinated group. Bring the final analysis and your personal questions to your prenatal care team when it becomes available.
What happens next
A final analysis using more sophisticated epidemiologic methods will follow the interim results.
Further reading
For more on the topic, explore our Pregnancy coverage.
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Would you feel comfortable getting an RSV vaccine during pregnancy to protect your baby?
