Babies get RSV (respiratory syncytial virus) the same way they catch most respiratory infections: by breathing in droplets from someone who is sick or by touching a contaminated surface and then touching their face. What makes RSV especially hard to avoid is how easily it spreads through households and how long it lingers on everyday objects like crib rails and countertops.
How RSV Reaches Your Baby
RSV spreads through respiratory droplets. When someone infected with the virus coughs or sneezes, tiny droplets land on nearby surfaces or travel directly into a baby’s eyes, nose, or mouth. Babies can also pick up the virus by touching a contaminated surface and then rubbing their face, which infants do constantly.
The virus is surprisingly durable on hard surfaces. RSV can survive for many hours on tables, crib rails, doorknobs, and toys. On softer surfaces like hands and tissues, it doesn’t last as long, but it persists long enough for a quick face touch to transfer the virus. This is one reason RSV tears through households and daycare settings so efficiently: a single sick child can leave the virus on shared toys, highchair trays, and changing tables throughout the day.
Who Typically Brings RSV Home
The most common scenario is an older sibling or a parent carrying RSV home without realizing it. In older children and adults, RSV often looks like a mild cold: runny nose, cough, maybe a low fever. The person may not think twice about snuggling or feeding the baby while mildly symptomatic. But that same virus can hit an infant much harder because their airways are so small that even modest swelling creates breathing problems.
Daycare is another major exposure point. Children in group care settings pass respiratory viruses back and forth constantly, and an older sibling attending daycare is one of the most well-established risk factors for an infant catching RSV at home. Visitors, caregivers, and anyone spending close time with a baby during RSV season (typically fall through early spring in most of the U.S.) can also be a source.
Which Babies Face the Highest Risk
Nearly all children catch RSV by age two, but some babies are far more likely to end up in the hospital. The youngest infants are the most vulnerable. Before new prevention tools became available, roughly 22 out of every 1,000 babies under three months old were hospitalized for RSV each season. Even with newer preventive options, the rate for that age group remains around 10 to 12 per 1,000.
Certain conditions raise the stakes further:
- Premature birth, especially babies who needed oxygen or other respiratory support
- Chronic lung disease requiring ongoing treatment like supplemental oxygen or corticosteroids
- Significant congenital heart disease
- Weakened immune systems from any cause
- Cystic fibrosis with signs of severe lung involvement
American Indian and Alaska Native children also have higher hospitalization rates for RSV and are specifically identified as a higher-risk group in current guidelines.
How Long a Sick Baby Can Spread It
People with RSV are typically contagious for three to eight days, though infants and people with weakened immune systems can shed the virus for up to four weeks. That extended shedding window means a baby who catches RSV can continue spreading it to siblings and household members well after the worst symptoms have passed. The virus is most contagious during the first few days of symptoms, when coughing and sneezing are most frequent.
Practical Ways to Reduce Exposure
Because RSV lives on surfaces for hours, regular hand washing is the single most effective everyday measure. Wash your hands before picking up, feeding, or touching the baby’s face. Ask anyone who holds the baby to do the same. Clean high-touch surfaces like crib rails, changing tables, and toys frequently during RSV season.
Keep sick visitors away. This sounds obvious, but because RSV mimics a mild cold in adults and older kids, people often underestimate their symptoms. Even a “just a little stuffy” older sibling can pass along a virus that’s far more serious for an infant. When possible, limit the baby’s exposure to crowded indoor spaces during peak RSV months.
Prevention Tools That Now Exist
Two newer options can give babies a head start against severe RSV. One is a monoclonal antibody given directly to the infant, typically as a single injection before or during RSV season. It provides ready-made protection rather than requiring the baby’s immune system to build its own response. This is recommended for all infants entering their first RSV season, with a second dose considered for higher-risk children heading into their second season.
The other option is a maternal vaccine given during pregnancy. When a pregnant person receives the vaccine between 32 and 36 weeks of gestation, their body produces antibodies that cross the placenta and protect the baby after birth. In clinical trials, this approach reduced the risk of a baby being hospitalized for RSV by 57% and the risk of needing any healthcare visit for RSV by 51% within the first six months of life.
Recent surveillance data shows these tools are making a measurable difference. RSV hospitalization rates among the youngest infants (under three months) dropped by roughly 45 to 52% during the 2024-25 season compared to pre-prevention baselines. Most infants only need one form of protection, not both. Babies born to mothers who received the vaccine during pregnancy generally don’t also need the antibody injection unless they have specific high-risk conditions.