Pregnant for RSV season? When the shot helps and when babies still need antibodies

If you are pregnant ahead of the 2026-27 RSV season, the main question is not whether RSV matters. It is which prevention path fits your timing: the maternal RSV shot during pregnancy, or a long-acting RSV antibody for your baby after birth. That question is especially timely in July because, in most of the continental United States, the maternal vaccination window opens in September.

Two June 2026 developments make this more relevant for families. A June 5 JAMA Network Open study added real-world evidence that maternal RSV vaccination was associated with fewer RSV hospitalizations in very young infants. Then on June 10, ACOG released its 2026 maternal immunization schedule. But the core CDC message did not change: most babies should be protected by either maternal vaccination during pregnancy or an infant RSV antibody after birth, not both.

The first rule to know: most families will use one path, not both

CDC recommends two main ways to protect babies from severe RSV in the first season of life. One is maternal vaccination during pregnancy with Pfizer’s Abrysvo. The other is a long-acting infant RSV antibody after birth, such as nirsevimab or clesrovimab.

For most babies, this is an either-or decision. If the pregnancy vaccine is given in the recommended time window and the baby is born at least 14 days later, the infant usually does not also need an RSV antibody. That gap matters because it takes time for the pregnant person’s immune system to make antibodies and pass them across the placenta.

The infant products are preventive antibodies, not routine childhood vaccines. Their practical role is to give direct protection to babies who were not covered well enough by maternal vaccination during the current pregnancy.

When the maternal shot helps most

In most of the continental U.S., CDC recommends one dose of maternal RSV vaccine during 32 weeks 0 days through 36 weeks 6 days of pregnancy, given from September through January. The timing is designed so the baby has protection during the first RSV season, when hospitalization risk is highest in early infancy.

This also means the shot is not the best fit for every pregnancy. If someone is already more than 36 weeks 6 days pregnant, CDC says there is unlikely to be enough time for antibodies to develop, cross the placenta, and protect the baby. In that situation, the better plan is usually to protect the newborn with the infant antibody after delivery.

CDC also does not currently recommend another maternal RSV dose in a later pregnancy if the pregnant person already received this vaccine during a previous pregnancy. In that later pregnancy, the infant should usually get RSV antibody protection after birth instead. ACOG’s 2026 maternal immunization schedule makes the same practical point by noting that repeat maternal vaccination is not indicated in subsequent pregnancies.

When the baby still needs an RSV antibody

According to CDC, an infant younger than 8 months should receive an RSV antibody if the mother was not vaccinated during the current pregnancy, if the vaccination status is unknown, or if the baby was born within 14 days after maternal vaccination.

In most of the continental U.S., babies born during October through March should ideally get that dose during the birth hospitalization or within 1 week after birth. Babies born outside that window can usually get it shortly before the next RSV season starts.

CDC also leaves room for rare exceptions after maternal vaccination. An infant RSV antibody may still be considered when a clinician thinks the added benefit is important, including when:

the mother may not have mounted an adequate immune response,
a medical condition may have reduced antibody transfer across the placenta,
the infant lost maternal antibodies after cardiopulmonary bypass, ECMO, or exchange transfusion, or
the infant has unusually high risk for severe RSV, such as certain serious heart or lung problems.

Local timing can differ. CDC notes that Alaska and some tropical climates, including southern Florida, Hawaii, Puerto Rico, Guam, the U.S. Virgin Islands, and U.S.-affiliated Pacific Islands, may use different seasonal timing because RSV circulation is less predictable there.

What the new June study changes, and what it does not

The June 5 JAMA Network Open study matters because it looked at real-world use after maternal RSV vaccination entered practice, not just results from the original clinical trial. Researchers used a retrospective case-control, test-negative design within a single western Pennsylvania health system and included 274 hospitalized infants age 90 days or younger.

The study estimated maternal vaccination effectiveness at 67.6% against RSV-associated acute respiratory illness hospitalization and 69.0% against RSV-related lower respiratory tract disease hospitalization in the first 90 days of life. Those are encouraging findings and broadly consistent with the trial-era evidence.

But the study does not settle every family decision. It was observational, not a randomized trial. It came from one health system, involved a relatively modest number of RSV cases, and the confidence intervals were fairly wide. It also was not a head-to-head comparison between maternal vaccination and infant antibody products. So the new study strengthens confidence that maternal vaccination can help, but it does not replace CDC’s timing rules or individualized counseling about which option fits a specific pregnancy and delivery timeline.

Safety questions and what remains unsettled

The FDA prescribing information for Abrysvo says a numerical imbalance in preterm births was observed in vaccine recipients compared with placebo recipients in two clinical studies. FDA also says the available data are insufficient to establish or exclude a causal relationship.

That is why U.S. use in pregnancy is limited to 32 through 36 weeks of gestation, and why the label says to avoid use before 32 weeks to reduce the potential risk of preterm birth. That wording does not mean the vaccine has been proven to cause preterm birth. It means the safety signal has not been fully resolved, so the approved gestational window remains narrow.

Another unanswered question is repeat vaccination in later pregnancies. CDC says it is still evaluating whether future evidence could show enough benefit to change the current no-repeat recommendation.

A practical checklist to ask about now

What is my due date, and how many weeks pregnant will I be between September and January?
Will I still be in the 32 weeks 0 days to 36 weeks 6 days window during that period?
Did I already receive a maternal RSV vaccine in an earlier pregnancy?
Is there any reason delivery might happen less than 14 days after vaccination?
If the baby arrives before that 14-day mark, is the plan to give an infant RSV antibody before discharge or shortly after birth?
If my baby may need NICU care or has heart, lung, or immune problems, does that change the RSV plan?
If I live in a place with unusual RSV timing, does my local season differ from the usual continental U.S. schedule?
Will the hospital have the infant antibody available, and what will insurance, Medicaid, or hospital billing look like?

Coverage questions are worth asking early. CDC says many private plans cover nirsevimab and most cover the maternal RSV vaccine, but out-of-pocket costs can vary by plan. For eligible children, nirsevimab is also covered through the Vaccines for Children program.

The bottom line for July 5, 2026, is fairly straightforward. The new study supports maternal RSV vaccination as a useful option when pregnancy timing lines up well. But the practical question families should ask before the fall RSV season starts is still the same: will this baby be best protected by the maternal shot during pregnancy, or by an RSV antibody after birth?

If your newborn later develops trouble breathing, pauses in breathing, blue lips, or poor feeding, seek urgent medical care rather than waiting for a routine visit.

Sources

Editorial note: Weence articles are researched from cited public-health, medical, regulatory, journal, and reputable news sources and may be drafted with AI assistance. They are checked for source support, clarity, and safety guardrails before publication.

This article is for general informational purposes only and is not medical advice. Research findings can be early or incomplete, and health guidance can change. Always talk with a qualified healthcare professional about personal symptoms, diagnosis, medications, vaccines, screenings, or treatment decisions. If you think you may have a medical emergency, call emergency services right away.