When During Pregnancy Is the RSV Vaccine Given?

Respiratory syncytial virus (RSV) is a common respiratory infection that can be serious in young infants. In August 2023, the U.S. Food and Drug Administration (FDA) approved a maternal RSV vaccine (Abrysvo®) to help protect babies from severe RSV disease in their first months of life. The key question for expectant parents and care providers is: when during pregnancy should this vaccine be administered for optimal benefit?

Why a Maternal RSV Vaccine?

• RSV is a leading cause of hospitalization in infants under 6 months.
• Newborns rely on antibodies passed from their mother before birth.
• Vaccinating the pregnant parent boosts these protective antibodies.
• Higher antibody levels at birth help babies fight RSV until their own immune system matures.

Optimal Timing: 32 to 36 Weeks Gestation

All major health authorities—including the CDC, ACOG (American College of Obstetricians and Gynecologists) and the FDA—recommend a single dose of RSV vaccine during the late third trimester, ideally between 32 and 36 weeks of pregnancy. Here’s why that window is critical:

• Peak Antibody Transfer
– The placenta transfers the most antibodies in the final weeks of gestation.
– Vaccination at 32–36 weeks maximizes the amount of RSV-fighting antibodies the baby receives at birth.

• Delivery Flexibility
– If labor starts early (but after 28 weeks), antibodies are still higher than if vaccinated too early.
– Scheduling between 32 and 36 weeks allows some leeway for minor shifts in appointment timing.

• Safety Profile
– Clinical trials showed no increase in preterm birth or other obstetric complications when given in this window.
– Side effects in pregnant people have been similar to other routine vaccines (see next section).

Safety and Side Effects

RSV vaccine during pregnancy has been studied in thousands of women. Overall, it has a reassuring safety profile:

Common side effects (mild to moderate)
• Soreness at the injection site
• Low-grade fever (under 101°F)
• Fatigue or headache
• Muscle aches

When to Contact Your Doctor
• High fever (over 101°F) that doesn’t respond to acetaminophen
• Signs of a severe allergic reaction—hives, swelling of face or throat, difficulty breathing
• Intense pain, redness or swelling beyond the injection site

Benefits for Your Baby

By receiving the RSV vaccine between 32 and 36 weeks, your baby will be born with higher levels of protective antibodies. Studies show:

• Up to 82% reduction in RSV-related hospitalizations in the first 3 months of life
• Fewer doctor or emergency visits for RSV infections
• Reduced need for supplemental oxygen or intensive care

This protection bridges the gap until infants are old enough to receive their own RSV vaccines or monoclonal antibody therapies (currently approved for certain high-risk infants starting at birth).

Who Should Get the RSV Vaccine?

The RSV vaccine during pregnancy is recommended for all pregnant individuals, regardless of age or medical history, with these considerations:

• Ideal timing: 32–36 weeks gestation.
• If you miss that window, speak to your obstetrician about whether vaccination at 28–31 weeks or after 36 weeks still offers some benefit.
• No prior dose is needed in earlier pregnancies; it is a single‐dose regimen per pregnancy.
• If you’ve already had RSV, vaccination still boosts protective antibodies.

Preparing for Vaccination

1. Schedule your prenatal visit around 32–36 weeks and let your provider know you wish to receive the RSV vaccine.
2. Review your vaccine history—other routine shots (Tdap, flu) can typically be given at the same visit.
3. Discuss any previous severe allergic reactions to vaccines or injectable medications.

After the shot, stay for a brief observation period (usually 15 minutes) to monitor for immediate reactions. Drink plenty of fluids, and you may use over-the-counter acetaminophen if you experience mild fever or aches.

What If You Deliver Early?

Even if you go into labor before 36 weeks, having your vaccine given as early as 28 weeks still provides some antibodies to your baby. Studies indicate:

• Babies born at 28–31 weeks after maternal vaccination still have significantly higher RSV antibody levels compared to babies whose mothers were unvaccinated.
• The closer the vaccination is to delivery, the higher the antibody levels—but any increase is beneficial.

Free, Online Symptom Check

If you or your baby develop respiratory symptoms—or you simply want peace of mind—you might consider a free, online symptom check, using the doctor approved Ubie Symptom Checker. It can help you decide whether to manage symptoms at home or seek medical care.

Key Takeaways

• RSV can be dangerous for newborns; maternal vaccination fills the immunity gap.
• The best time for the RSV vaccine during pregnancy is between 32 and 36 weeks gestation.
• A single dose boosts antibody levels passed to your baby, reducing severe RSV illness.
• Side effects are generally mild and similar to other vaccines.
• Speak to your doctor if you miss the ideal window or have any concerns.

Speak to a Doctor

Always discuss any serious or life-threatening symptoms with your healthcare provider right away. Your doctor can help you weigh benefits and risks, adjust timing for high-risk pregnancies, and ensure both you and your baby get the best possible protection against RSV.