Kids get RSV (respiratory syncytial virus) the same way they pick up most respiratory infections: by breathing in virus-laden droplets, touching contaminated surfaces, or having close contact with someone who’s infected. It spreads remarkably easily, and most children will catch RSV at least once before their second birthday.
The Three Main Ways RSV Spreads
RSV enters a child’s body through the eyes, nose, or mouth. There are three common routes that get it there:
- Respiratory droplets. When someone with RSV coughs or sneezes nearby, tiny droplets carrying the virus can land directly on a child’s face or be inhaled.
- Direct contact. Kissing a child’s face, sharing cups, or close physical contact with an infected person can transfer the virus.
- Contaminated surfaces. A child touches a doorknob, toy, or table that has the virus on it, then rubs their eyes or puts their fingers in their mouth.
That last route is especially relevant for young kids, who touch everything and constantly bring their hands to their faces. RSV can survive on hard surfaces for several hours, which means a single sick child in a room can leave the virus on shared toys, highchair trays, and countertops long after they’ve moved on.
Where Kids Are Most Likely to Catch It
Daycare centers and preschools are the most common places children encounter RSV. Dozens of toddlers sharing toys, sitting close together, and not yet grasping the concept of covering a cough creates an ideal environment for transmission. Once one child in a daycare group has RSV, it tends to move quickly through the room.
The household is the other major setting. Older siblings who pick up the virus at school or daycare often bring it home. In an older child or adult, RSV can look like a mild cold, with a runny nose and slight cough. That person may not seem very sick at all, but they’re still shedding enough virus to infect a baby through normal caregiving, from feeding and diaper changes to bedtime cuddles. Adults with RSV sometimes don’t realize they have anything more than a minor cold, yet they can easily pass the virus to an infant during routine contact.
When RSV Season Peaks
RSV follows a seasonal pattern in the United States, with cases climbing in the fall and peaking in late December or early January. The timing varies by region. The Southeast tends to see its peak earlier in the season, while northern and western states may peak later. Activity generally tapers off by spring.
This fall-through-spring window, roughly October to March, is when the vast majority of infections happen. If your child is in daycare or has school-age siblings, that’s the period when exposure is most likely.
How Long a Sick Child Can Spread It
Children with RSV are typically contagious for 3 to 8 days, starting a day or two before symptoms appear. That pre-symptomatic window is one reason RSV moves so efficiently through groups of kids: a child can be spreading the virus before anyone knows they’re sick. Very young infants and children with weakened immune systems can sometimes shed the virus for as long as four weeks, which makes protecting newborns in a household with a sick toddler especially challenging.
The incubation period, the gap between exposure and first symptoms, is usually 4 to 6 days. So if your child was around a sick playmate on Monday, you might not see a runny nose until Friday or Saturday.
Why Babies and Toddlers Are Hit Hardest
RSV causes cold-like symptoms in most older children and adults, but in babies under 12 months, the infection can move into the smaller airways of the lungs. Their airways are physically tiny, so even modest swelling and mucus buildup can make breathing difficult. Premature infants, babies with congenital heart conditions, and children with weakened immune systems face the highest risk of severe illness.
Reinfection throughout life is normal. RSV doesn’t produce lasting immunity the way some viruses do, so children can catch it more than once. Second and third infections tend to be milder, though, as the immune system builds partial protection with each exposure.
Reducing Your Child’s Exposure
Because RSV spreads so readily, complete avoidance is difficult, but a few practical steps lower the odds:
- Handwashing. Soap and water is effective at removing RSV from skin. Alcohol-based hand sanitizers also inactivate the virus. Washing hands before picking up or feeding a baby is one of the simplest protections available.
- Surface cleaning. Disinfectants based on alcohol, hydrogen peroxide, or aldehyde all destroy RSV on surfaces. Regularly wiping down shared toys and high-touch areas during RSV season helps, particularly in homes with both a baby and an older child in daycare.
- Limiting close contact when someone is sick. If an older sibling or adult in the house has cold symptoms during RSV season, keeping some distance from the baby and being diligent about hand hygiene before touching the infant can reduce transmission.
Immunization Options for Infants
Two approaches now exist to protect babies from severe RSV. One is a vaccine given to the pregnant mother (Pfizer’s Abrysvo), which passes protective antibodies to the baby before birth. The other is a direct injection of lab-made antibodies given to the infant. Both aim to provide protection during the months when a baby’s immune system is least equipped to handle the virus on its own.
The CDC recommends an RSV antibody injection for infants younger than 8 months entering their first RSV season if the mother did not receive the RSV vaccine during pregnancy, if her vaccination status is unknown, or if the baby was born within 14 days of the mother’s vaccination. For children 8 to 19 months old, a second-season dose is recommended only for those at higher risk: children with chronic lung disease, severe immune deficiency, cystic fibrosis with significant lung involvement, or American Indian and Alaska Native children.
In clinical trials, the antibody injection nirsevimab reduced RSV-related hospitalizations by about 81% and prevented roughly 79% of lower respiratory infections that required medical attention. A newer option, clesrovimab, showed 91% effectiveness against RSV hospitalizations in its trials. Both are given as a single injection, typically in October or November, or within the first week of life for babies born during RSV season.