Respiratory syncytial virus (RSV) is such a common virus that nearly all adults and young children are affected by it sooner or later.

The virus and its accompanying cold-like symptoms will typically last a week or two. Although it usually runs its course without any major problems, RSV can be more serious, especially in babies and young children.

While you may not even know that your baby’s cold- or flu-like symptoms are due to an RSV infection,[1] some little ones wind up getting very sick with the virus. In those situations, and in children with other health conditions, RSV can cause more serious illness and even lead to complications.

Here's more on how to protect your baby, how to manage and treat RSV symptoms, when to see the doctor, and how to prevent your little one from catching it in the first place.

What is RSV in babies?

RSV is a contagious virus that's spread just like the common cold, often between October and April. Almost every child will get RSV by the age of 2, and for the majority of babies, the illness is on the milder side, with symptoms lasting for about one or two weeks.

But some infants have a higher risk of severe RSV, including premature babies; those whose lungs are underdeveloped; and babies born with heart conditions, lung problems or immune deficiencies. Other babies just happen to get a more serious bout of RSV, even if they don't have chronic health conditions that would make them susceptible.

In all those cases, RSV can escalate from mild to severe, and can lead to pneumonia or bronchiolitis, an infection that causes the small, inner branches in the lungs to swell and can make breathing more difficult.[2]

In fact, RSV is a leading cause of severe bronchiolitis among young children under 1 year old. About 70 percent of infants are infected with RSV during their first year of life. And 2 to 3 out of every 100 babies under the age of 6 months who get RSV may need to be hospitalized and given oxygen or other help breathing.[3]

What are the signs of RSV in babies?

Most of the time, babies with RSV have mild, cold- or flu-like symptoms that tend to peak on the third to fifth day of the illness. The symptoms of RSV usually appear two to eight days after contracting the virus, and a child with RSV can be contagious for at least three to eight days before showing symptoms.

Common symptoms of RSV in infants include:[4]

Babies who are younger than 6 months old may show different symptoms of an RSV infection, including:

  • Irritability
  • Decreased activity
  • Loss of appetite
  • Apnea (pauses during breathing)

More serious symptoms of RSV (and complications like bronchiolitis) include the following and warrant an immediate call to the doctor or trip to urgent care or the ER, according to the American Academy of Pediatrics (AAP):

  • Labored breathing or having trouble breathing
  • Wheezing
  • Fast breathing
  • Flaring of the nostrils, head bobbing while breathing
  • Belly breathing, tugging between the ribs and/or in the lower part of the neck
  • Grunting while breathing
  • Dehyrdation

How do babies get RSV?

An RSV infection can be spread through the air by coughing or sneezing, which is how babies often catch the virus.

RSV can also survive on surfaces for up to six hours, which makes it easy to pick up. Children can get RSV by touching an infected playmate’s hand and then putting their own hands into their mouths, eyes or noses; picking up toys a sick child was using and then putting their hands into their mouths; or sharing cups and utensils with someone who has the virus.[5]

The babies who are at most risk of a severe infection include:[6]

  • Low birth weight or premature babies (especially those born before week 29)
  • Babies with a chronic lung disease
  • Babies who have certain types of heart defects
  • Babies with weakened immune systems
  • Babies who are 3 months old or younger at the start of the RSV season

But remember, not all babies who wind up with serious RSV have any chronic or other health conditions.

How is RSV treated in babies?

There is currently no medication or other treatment specifically designed for RSV in babies and young children who already have RSV.

However, the Food & Drug Administration (FDA) approved a preventive antibody treatment called Beyfortus for babies and toddlers up to 20 months old.[7] Also known as nirsevimab, it's designed to protect infants and young children by providing antibodies that recognize RSV and fight it off, as well as prevent serious illness, if those kids are exposed to the virus. 

The FDA also approved the first RSV vaccine for adults (60 and older) in May 2023, and in August 2023 approved the RSV vaccine for pregnant women to protect their newborn babies from birth up to age 6 months. 

In the meantime, there are ways to manage your little one's symptoms at home if your child does catch it and the virus stays on the milder side, just like you would for a cold or the flu.[8] Here are some ways to help your tot feel better:

  • Keep your child hydrated. Your baby may not feel like drinking when he’s sick, but he’ll need plenty of liquids. If he doesn’t feel like breastfeeding, you can offer him pumped or expressed milk in a bottle or cup.
  • Use a humidifier. A humidifier will help break up mucus and ease congestion, which can help your child breathe easier. Avoid using hot-water humidifiers, however, which can cause burns if they tip over.
  • Keep his nose clear. Use a bulb syringe to suction mucus out of his nose, which can also make it easier for him to breathe. You can also clear a stuffy nose with frequent blowing or an infant aspirator. Try doing this before feeds so your little one can breathe wihle eating.
  • Use OTC pain relievers to bring down a fever. To ease a low-grade fever, you can give acetaminophen (like Tylenol) to babies 3 months and older with your doctor's approval or ibuprofen to babies 6 months and older.[9]
  • Do not give your child aspirin or cough and cold medications. If your baby is under 2 months, don’t give him any medication unless it’s been approved by your doctor first.[10]

When to seek medical care for a baby with RSV

If your baby was born prematurely, suffers from congenital heart disease or has other problems that increase his risk of complications, contact your doctor immediately if you notice serious cold symptoms such as:

  • Loss of appetite
  • Fever
  • Runny nose
  • Coughing
  • Retractions (fast breathing or sucking in the stomach while breathing)

Remember that while cold symptoms may not be a concern for babies who are not at high risk of RSV complications, the symptoms of a more severe RSV infection that warrant a call to the doctor or trip to the ER include:

  • Fever of 100.4 degrees Fahrenheit or higher in babies under 3 months old[11]
  • Fever of 101 to 103 degrees F that persists for longer than 24 hours in babies 3 to 6 months old
  • Fever of 103 F or higher in children older than 6 months that lasts for more than 24 hours
  • Apnea
  • Breathing that’s labored, rapid or accompanied by a lot of wheezing, flaring of the nostrils and/or rhythmic grunting during breathing
  • Gray or bluish skin, tongue or lip color
  • Worsening cough or coughing up mucus
  • Extreme lethargy
  • Symptoms of dehydration — for example, fewer than one wet diaper every eight hours

Can RSV be prevented in babies?

Unfortunately, RSV is one of those infant and childhood illnesses that can't fully be prevented, but there are ways to protect your little one, including:

  • Get the RSV vaccine when you're pregnant. The RSV vaccine, approved in 2023 for pregnant women between 32 and 36 weeks along, protects babies from catching the virus and becoming seriously ill after birth.
  • Ask your doctor about the RSV antibody treatment for babies. Some babies will be eligible for the preventive RSV antibody treatment nirsevimab, including those born during RSV season whose mothers didn't get the vaccine while they were pregnant. Talk to your practitioner to see whether the one-dose shot is right for your child. Nirsevimab reduces the risk of severe RSV by about 80%, according to the Centers for Disease Control and Prevention (CDC).
  • Wash your hands. Make sure that everyone in the family — including toddlers — washes their hands regularly with soap and water, scrubbing for at least 20 seconds.
  • Get the flu vaccine. Everyone who’s 6 months old or older should get the flu shot to limit the chances of becoming infected with other viruses that can weaken the immune system during the winter season, when RSV infection rates are higher.
  • Don't smoke. You can help protect your child by not smoking or vaping, since smokers are at greater risk of developing respiratory infections that can then be passed on to little ones and secondhand smoke and vaping fumes can be harmful to children and others in the house.
  • Breastfeed (if possible). Breastfeeding can help pass along antibodies that protect against RSV.
  • Wipe out germs. Keep some disposable disinfectant wipes on hand and wipe down surfaces in your home such as bathroom counters, faucets, doorknobs and cellphones, which could be harboring viruses that family members or friends were carrying. Regularly sanitize toys, pacifiers and items that your child tends to chew on.
  • Limit or avoid exposure to those with cold and flu symptoms that could be signs of RSV. Newborns and babies are especially vulnerable since their immune systems aren't fully developed yet. Keeping your baby away from sick people as much as possible (even in the same house), wearing face masks (if those with symptoms are kids over 2 and adults), and other similar measures can help. 

Thankfully, almost all children will recover from an RSV infection on their own, without any need for a trip to the doctor's or the hospital. Still, call your pediatrician if you have any concerns, especially if your little one has other health conditions that may put him more at risk, or winds up with a more serious case of the virus.