Protecting a baby from RSV starts with a combination of immunization, everyday hygiene, and limiting exposure during peak season. RSV (respiratory syncytial virus) circulates most heavily from mid-September through March or April, and nearly all children catch it before age two. For most, it causes cold-like symptoms. For young infants, especially those under six months, it can lead to serious breathing problems, hospitalization, or worse. The good news: several effective tools now exist to dramatically cut that risk.
Immunization Options for Infants
The most powerful prevention tool available is nirsevimab, an antibody injection given directly to babies. It’s recommended for all infants younger than 8 months who are born during or entering their first RSV season, as long as the mother didn’t receive the RSV vaccine during pregnancy. In real-world data, nirsevimab was at least 70% effective at preventing RSV hospitalizations. Clinical trials showed even stronger results: about 80% efficacy against hospitalization and 79% against doctor-visit-level lower respiratory infections.
The dose depends on weight. Babies under 11 pounds get a 50 mg injection; those 11 pounds or more get 100 mg. It’s a single shot, not a series, and it provides protection throughout the RSV season. A second antibody product, clesrovimab, showed 91% efficacy against RSV hospitalization through the first 150 days after injection in clinical studies.
For children between 8 and 19 months with certain health conditions, a higher dose of nirsevimab (two injections totaling 200 mg) is recommended heading into their second RSV season. An older medication, palivizumab, requires monthly injections throughout the season and is reserved for the highest-risk babies, including those born extremely premature, those with significant heart or lung conditions, and those with severely weakened immune systems.
Vaccination During Pregnancy
If you’re pregnant, you can pass RSV-fighting antibodies to your baby before birth. The maternal RSV vaccine is given as a single dose between 32 and 36 weeks of pregnancy, ideally sometime between September and January. Those antibodies cross the placenta and give your newborn immediate protection from the moment they’re born, covering their first RSV season as the protection gradually fades over the following months.
Timing matters. Getting vaccinated after 36 weeks and 6 days doesn’t leave enough time for antibodies to build up and transfer to the baby. If you received the vaccine during pregnancy, your infant generally does not also need the antibody injection, unless they were born within 14 days of your vaccination (again, not enough transfer time). If your vaccination status is unknown, your baby’s doctor will typically recommend the infant injection to be safe.
Everyday Hygiene That Actually Helps
RSV spreads through respiratory droplets and contaminated surfaces. The virus can survive for many hours on hard surfaces like tables, countertops, and crib rails, though it dies more quickly on soft surfaces like tissues and skin. That makes hand hygiene the single most important daily habit for protecting your baby.
Wash your hands with soap and water for at least 20 seconds before picking up, feeding, or caring for your infant. Ask anyone who holds the baby to do the same. If soap isn’t available, hand sanitizer with at least 60% alcohol works as a backup. Regularly wipe down frequently touched surfaces in your home, especially during RSV season. Clean pacifiers, bottles, and toys that other children may have handled.
Limiting Exposure During Peak Season
RSV season can start as early as mid-September and stretch into March or April. During these months, being strategic about your baby’s exposure to crowds and sick contacts makes a real difference. Avoid bringing young infants to crowded indoor spaces when possible. If your baby is in daycare, look for programs that actively monitor children for illness symptoms before drop-off and isolate sick children from the group.
Ask family members and friends not to visit if they have cold symptoms, even mild ones. Adults with RSV often look like they just have a regular cold, but they’re fully capable of passing the virus to a vulnerable infant. This can feel socially awkward, but it’s one of the most effective things you can do during your baby’s first winter.
Keep Smoke Away From Your Baby
Secondhand smoke exposure makes RSV infections significantly worse. In a study of hospitalized children with RSV, those exposed to cigarette smoke had notably lower oxygen levels on admission and higher clinical severity scores compared to unexposed children. Twenty-eight percent of smoke-exposed babies needed supplemental oxygen on arrival at the hospital, compared to just 4% of unexposed babies. Cotinine, a marker of tobacco smoke exposure, was the single strongest predictor of low oxygen levels in these infants. If anyone in your household smokes, keeping smoke completely away from the baby (not just smoking in another room) is critical.
Breastfeeding Offers Additional Protection
Breast milk contains antibodies that target RSV directly. Research on mother-infant pairs in Nepal found that IgG antibodies in breast milk, specifically those targeting a key protein on the surface of RSV, were lower in mothers whose babies went on to develop RSV illness compared to mothers whose babies stayed healthy. This protective effect was most relevant in the first six months of life. Breastfeeding won’t make your baby immune to RSV, but it adds a meaningful layer of defense on top of immunization and hygiene measures.
Which Babies Face the Highest Risk
All young infants are vulnerable to RSV, but some face a much higher chance of severe illness. The risk is greatest for premature babies (especially those born before 29 weeks), infants with chronic lung disease, babies born with heart defects, children with weakened immune systems, and those with neuromuscular conditions that make it hard to cough or clear mucus. American Indian and Alaska Native children also face elevated risk. If your baby falls into any of these categories, talk to their pediatrician about which immunization option fits best and whether monthly palivizumab injections are warranted.
Signs That RSV Has Become Serious
Even with precautions, some babies will catch RSV. Most recover on their own, but knowing what serious breathing trouble looks like lets you act fast. Watch for rapid, shallow breathing, or visible effort with each breath where the chest muscles and skin pull inward. Wheezing (a high-pitched sound when breathing out), poor feeding, unusual sleepiness, and irritability are all warning signs that the infection has moved into the lower airways. In severe cases, RSV can cause bronchiolitis or pneumonia. If your baby is struggling to breathe, refusing to eat, or seems unusually lethargic, that warrants immediate medical attention.