Protecting a newborn from RSV (respiratory syncytial virus) now involves two powerful medical tools that didn’t exist a few years ago: a maternal vaccine given during pregnancy and a preventive antibody injection given to the baby after birth. Combined with practical hygiene measures, these options can reduce the risk of severe RSV illness by 70% to 80% or more. Here’s how each strategy works and what you can do before and after your baby arrives.
Get the Maternal RSV Vaccine During Pregnancy
The CDC recommends a single dose of the maternal RSV vaccine (Abrysvo) between 32 and 36 weeks of pregnancy, given sometime during September through January. The vaccine prompts your body to produce antibodies against RSV, which cross the placenta and provide your baby with protection from birth.
The results are striking. In clinical trials, the maternal vaccine reduced the risk of severe RSV outcomes in infants, including dangerously low oxygen levels, ICU admission, and the need for mechanical ventilation, by 82% within the first three months of life and 69% within the first six months. That early window of protection matters most because newborns are at their highest risk during those initial weeks and months.
If your due date falls between late October and the end of January, the timing lines up naturally with RSV season. Talk with your OB or midwife about scheduling the shot during a routine third-trimester visit.
Preventive Antibody Injections for Infants
If you didn’t receive the maternal vaccine, or even if you did and want to discuss additional protection, your pediatrician can give your baby an antibody injection called nirsevimab (Beyfortus). This is not a vaccine. It delivers ready-made antibodies directly into your baby’s system, offering immediate protection against RSV without requiring the baby’s immune system to build its own response.
Nirsevimab is recommended for all infants under 8 months old entering their first RSV season. The dose depends on weight: 50 mg for babies under 5 kg (about 11 pounds) and 100 mg for those 5 kg and above. Babies between 8 and 19 months who are at higher risk can receive a 200 mg dose before their second RSV season.
Real-world data show nirsevimab is at least 70% effective at preventing RSV hospitalization. Pooled clinical trial data put its effectiveness at about 79% for preventing doctor visits related to RSV lower respiratory infections and roughly 81% for preventing RSV hospitalizations specifically. A newer option called clesrovimab is also available, with a single 105 mg dose for all eligible infants and a 91% effectiveness rate against RSV hospitalization through five months after injection.
Do Babies Need Both the Vaccine and the Injection?
Most infants don’t need both. If you received the maternal vaccine during the recommended window and your baby was born no more than 14 days before 32 weeks of gestation, your baby generally has adequate protection. The antibody injection is primarily recommended when the mother wasn’t vaccinated, when the baby was born prematurely before the vaccine’s antibodies could fully transfer, or when the baby has certain health conditions that put them at higher risk.
Know When RSV Season Hits
In the United States, RSV season typically begins in October, peaks in December, and tapers off by March or April. The season lasts roughly 27 weeks. This means babies born between October and March face the highest immediate exposure risk, while summer babies may encounter RSV later in their first year when they’re a bit more resilient.
Your timing decisions around immunization should align with this season. The maternal vaccine is recommended between September and January precisely because it takes a couple of weeks for antibodies to build and transfer. Similarly, the infant antibody injection is ideally given just before or early in the season so protection lasts through the peak months.
Everyday Measures That Reduce Exposure
RSV spreads through respiratory droplets when an infected person coughs or sneezes, and through direct contact with contaminated surfaces. The virus can survive for many hours on hard surfaces like tables, crib rails, and doorknobs, which is why hygiene habits matter as much as immunization.
Wash your hands with soap and water for at least 20 seconds before touching or holding your baby, and remind older children in the household to do the same. Clean frequently touched surfaces regularly. If friends or family visit, ask them to wash their hands before holding the baby. Anyone with cold-like symptoms, even mild ones, should wait to visit until they’ve been symptom-free. If you’re unsure about a visitor’s health, asking them to wear a mask is reasonable. One practical tip from pediatric specialists: ask visitors to avoid kissing the baby’s face and suggest kissing the baby’s feet instead.
Try to stay within your immediate family circle as much as possible for the first couple of months, particularly during RSV season. Crowded indoor spaces like shopping centers, waiting rooms, and large gatherings increase your baby’s exposure to respiratory viruses of all kinds.
Breastfeeding Adds Another Layer of Protection
Breast milk delivers antibodies directly to the surfaces of your baby’s airways and gut, where infections often take hold. Research published in The Journal of Infectious Diseases found that mothers with higher levels of RSV-targeting antibodies in their breast milk were less likely to have infants who developed RSV illness in the first months of life. Breastfed infants consistently show lower rates of RSV hospitalization and reduced disease severity compared to non-breastfed infants.
Breastfeeding won’t prevent RSV on its own, but it works alongside immunization and hygiene measures to strengthen your baby’s defenses during the most vulnerable period.
Recognizing RSV Early in Newborns
Even with the best prevention, some babies still catch RSV. Early symptoms look a lot like a common cold: runny nose, decreased appetite, and cough. In newborns, though, RSV can escalate quickly. Watch for coughing that progresses to wheezing or visible difficulty breathing. In very young infants under 6 months, RSV can cause apnea, which means pauses in breathing lasting more than 10 seconds.
Signs that your baby is working harder to breathe include flaring nostrils, the skin pulling in between the ribs or at the base of the throat with each breath (called retractions), and unusually fast breathing. A baby who is too tired to eat or who seems unusually limp or irritable needs prompt medical attention. Catching these signs early can make the difference between managing RSV at home and a hospital stay.
Extra Protection for High-Risk Babies
Some babies face greater danger from RSV because of underlying health conditions. Infants born very prematurely (before 32 weeks), babies with chronic lung disease who needed supplemental oxygen for at least 28 days after birth, children with severe immune deficiencies, and those with cystic fibrosis accompanied by serious lung problems or poor weight gain all fall into higher-risk categories. American Indian and Alaska Native children also face elevated RSV risk.
For these babies, the antibody injections (nirsevimab or clesrovimab) are the first-line protection. An older monthly injection called palivizumab (Synagis) is no longer routinely recommended but remains available for children between 8 and 19 months with specific high-risk conditions who can’t receive the newer options. If your baby was born prematurely or has a chronic health condition, your pediatrician will likely bring up RSV prevention as part of your discharge plan or early well-child visits.