Key takeaways: RSV causes mild colds in most people but can be serious for young babies. Protection comes from the RSV vaccine in pregnancy or an antibody shot (nirsevimab or clesrovimab) for babies under 8 months. Watch for fast breathing, pulling in at the ribs, and poor feeding.
Respiratory syncytial virus (RSV) infects nearly all children by age 2. For most, it’s a cold. But for young babies, it can cause bronchiolitis and pneumonia. RSV is the leading cause of hospitalization in U.S. infants. The good news: there are now very effective ways to protect your baby.
Who’s at Highest Risk?
- Babies under 6 months, especially under 2 months.
- Premature babies.
- Babies with chronic lung disease or congenital heart disease.
- Babies with weakened immune systems or neuromuscular conditions.
Prevention: Two Options
Most babies need one of these, not both:
1. RSV vaccine during pregnancy (Abrysvo).
Given between 32 and 36 weeks of pregnancy, typically from September through January in most of the U.S. Antibodies cross the placenta and protect the baby for the first months of life. Babies born at least 14 days after the vaccine generally don’t need the infant antibody shot in their first season.
2. RSV antibody shot for the baby (nirsevimab or clesrovimab).
A single injection of protective antibodies. The AAP’s 2026-27 recommendations call for RSV immunization for all infants younger than 8 months who are born during or entering their first RSV season, unless they’re protected by vaccination during pregnancy. Babies born shortly before or during RSV season should receive it within the first week, ideally before leaving the birth hospital.
Some babies at high risk of severe RSV also need a dose of nirsevimab before their second RSV season (ages 8 to 19 months). The AAP expanded these high-risk criteria in September 2026; ask your pediatrician if your child qualifies.
RSV season timing varies by region. In parts of the Southeast, including Florida, RSV can circulate earlier or longer, and timing recommendations may differ; ask your doctor.
Everyday Prevention
- Wash hands before touching your baby.
- Keep sick people away from your baby.
- Avoid crowds during RSV season in the first months.
- Don’t smoke or vape around your baby.
- Breastfeed if you can.
Symptoms
RSV often starts like a cold:
- Runny nose, congestion, sneezing.
- Cough.
- Decreased appetite.
- Fever (not always).
In young babies, it may progress over 3 to 5 days to:
- Fast breathing.
- Wheezing.
- Pulling in at the ribs or neck with breathing.
- Poor feeding.
- Pauses in breathing (apnea), especially in very young or premature babies.
Symptoms often peak around days 3 to 5.
Home Care
- Saline drops and nasal suction before feeds and sleep.
- Small, frequent feeds.
- Cool-mist humidifier.
- Keep your baby on their back to sleep on a flat surface.
- Antibiotics don’t work on RSV, and treatments like albuterol and steroids usually don’t help bronchiolitis in babies.
Go to the emergency room or call 911 if your baby:
- Has blue or gray lips, tongue, or skin.
- Has pauses in breathing.
- Is struggling to breathe, with ribs pulling in, grunting, nostril flaring, or head bobbing.
- Is breathing very fast (more than 60 breaths a minute).
- Is very sleepy, limp, or hard to wake.
Call your baby’s doctor promptly if your baby: is under 3 months with any fever of 100.4°F or higher, is feeding much less than usual, has fewer wet diapers, or is getting worse.
The Bottom Line
RSV can be serious for young babies, but prevention is better than ever. Ask about the RSV vaccine during pregnancy or the infant antibody shot. Watch for breathing trouble and poor feeding.
Want more support for your baby’s first year? My book, From First Breath to First Birthday, is available on Amazon.
Sources
- American Academy of Pediatrics Committee on Infectious Diseases. Recommendations for the prevention of RSV disease in infants and children: policy statement. Pediatrics. Published online September 2, 2026.
- Centers for Disease Control and Prevention. RSV immunization guidance for infants and young children. https://www.cdc.gov/rsv
- Hammitt LL, Dagan R, Yuan Y, et al. Nirsevimab for prevention of RSV in healthy late-preterm and term infants. N Engl J Med. 2022;386(9):837-846.
- Kampmann B, Madhi SA, Munjal I, et al. Bivalent prefusion F vaccine in pregnancy to prevent RSV illness in infants. N Engl J Med. 2023;388(16):1451-1464.
- Ralston SL, Lieberthal AS, Meissner HC, et al. Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics. 2014;134(5):e1474-e1502.
- American College of Obstetricians and Gynecologists. Maternal respiratory syncytial virus vaccination. Practice Advisory. https://www.acog.org
This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.
