By their second birthday, nearly all children in the United States will have had respiratory syncytial virus (RSV). This highly contagious virus causes inflammation of the respiratory tract, usually resulting in cold-like symptoms.

Most kids (and adults, who can get it too) with an RSV infection recover within a week or two, but it can be serious for those without strong immune systems, including infants and older adults, and for them it can be quite serious. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lungs) and pneumonia (a lung infection) in children younger than 1 in the U.S.

“The vast majority of kids who get RSV appear to have nothing worse than a simple cold, and never have to be hospitalized for RSV,” explains Magna Dias, MD, a Yale Medicine pediatric hospitalist (a physician who only sees patients in the hospital). “Some kids may get an ear infection or have a fever with it, so it’s important to have your pediatrician evaluate your child if you have any concerns. And good handwashing or using hand sanitizer will stop it from spreading.”

“With Yale Medicine pediatricians treating patients at Yale New Haven hospital locations in Bridgeport, Greenwich, New Haven, and New London, children can receive care throughout the state,” Dr. Dias adds. 

In mild cases of RSV, inflammation is limited to the upper respiratory tract (the nose and throat), most significantly causing a runny nose and nasal congestion. “The hallmark of RSV is that it causes a lot of mucus production that causes you to blow your nose more frequently,” Dr. Dias says.

Other symptoms may include a slight cough, a decrease in appetite, and low-grade fever. More serious RSV infections eventually reach down into the lower respiratory tract (bronchial tubes and lungs). A sign that the infection is worsening is when symptoms get more severe (coughing turning into wheezing, for example).

The runny nose and fever typically begin (then it worsens and peaks) three to five days after the infection starts. For some, those may be the only symptoms. But roughly half of all children who are infected for the first time experience the later-stage (and more intense) coughing and wheezing symptoms.

This can be serious for infants younger than 6 months. “For little babies who get RSV, having that much mucus obstructs their tiny nasal passages and their airways. This can create difficulty in their breathing, and sometimes their noses are so congested they have trouble breathing through their noses. Of course, they are going to choose to breathe [through the mouth] over eating, and that can lead to dehydration (loss of body fluids) and needing IV fluids,” says Dr. Dias.

RSV is very contagious. It can spread through the droplets released into the air when an infected person coughs or sneezes, or if you touch a contaminated surface, such as counters or doorknobs (where it can live for hours). It can also spread through direct contact (kissing the face of a child with RSV, for example).

People with RSV are contagious for three to eight days after exposure. But because their immune systems aren’t as good at eliminating the virus, some infants and others with weakened immune systems are contagious for as long as four weeks, even after they no longer have symptoms.

In the U.S., RSV infections are most common during the fall, winter, and spring seasons. 

People of any age can get an RSV infection, but previous exposure tends to reduce the severity of symptoms. Here is a list of those with the highest risk of becoming seriously ill from RSV: 

• Premature infants
• Very young children (under 6 months)
• Young children (under age 2) with congenital heart or chronic lung disease including asthma
• Young children and adults with weakened immune systems (from illness or medical treatments)
• Children with neuromuscular disorders that make it difficult for them to swallow or clear mucus secretions
• Older adults, in particular those with heart or lung disease

Generally, RSV is diagnosed by a medical professional, based on symptoms and a physical exam.

Your doctor will listen to your child’s lungs with a stethoscope to check for signs of pneumonia or bronchiolitis. RSV can be confirmed with lab tests using a nasal mucus swab, but testing will only be done if it will affect the treatment plan, explains Dr. Dias. 

“Most of the time, as with a cold, knowing it is RSV will not make a difference in our care, because the only real treatment for it is supportive care,” she says.

There is no specific treatment for RSV infections. In most cases, RSV infections—especially in healthy children and adults—will clear up within a week or two. Discomfort and fever can be treated with over-the-counter medications such as ibuprofen or acetaminophen. It’s also important to drink plenty of fluids to prevent dehydration.

A person with RSV (especially an infant younger than 6 months or an older adult) may need to be hospitalized if they become dehydrated or have ear pain or trouble breathing, which could be signs of a secondary infection such as an ear infection or pneumonia. Signs of dehydration in babies and young children include a dry mouth and tongue, crying without tears, lethargy, and dry diapers for eight hours or longer. Your child’s doctor will evaluate your child and recommend hospitalization, if necessary.

In the hospital, treatments may include intravenous fluids, or in severe cases, oxygen therapy or mechanical ventilation (having a breathing tube inserted through the mouth and down the airway). 

One of the most effective ways to prevent an RSV infection is to practice good hand hygiene. Wash and scrub your hands with water and soap regularly, and especially before holding your baby. Encourage older children and other caregivers to do the same. You can also limit your baby’s exposure to crowded places like shopping centers, where RSV may be prevalent, especially in the winter and spring.

If you have RSV (or any cold symptoms), reduce contagion by covering your mouth and nose when you cough and sneeze with either your shirt sleeve or a tissue (not your hands).

You should avoid close contact (kissing, shaking hands, sharing utensils and cups) with others, especially young children. And disinfect contaminated surfaces—everything from door knobs to countertops.

A medication called palivizumab is given (as a shot) to prevent severe RSV illness in children and infants who are considered at high risk of developing serious complications. The shot does not improve symptoms for kids already suffering from it, nor does it prevent infection with RSV.

“You need to get the shot every month during the season RSV is active in the community,” Dr. Dias explains. “For our high-risk kids, including babies born extremely prematurely, we will give it to them for their first year of life.”

Our pediatric specialists at Yale Medicine are experienced at treating RSV and any complications that may arise from the illness.

If your child requires hospitalization, Yale New Haven Children’s Hospital is ranked nationally among the top children’s hospitals in the country for the exceptional care it provides.