The respiratory tract is the parts of the body related to breathing, including the nose, windpipe, air passages in the lungs, and the lungs.

RSV is a virus that infects the respiratory tract.

RSV infections spread easily among babies and children, usually in winter and early spring. Nearly all children get the virus by age 4.

RSV causes runny nose, fever, cough, and wheezing.

Most children don't have problems, but severe infections cause trouble breathing and low oxygen levels.

Someone can have RSV more than once, but symptoms are usually milder after the first time.

What causes RSV infection?

RSV is one of many viruses that infect the respiratory tract. Others include the cold virus and the flu virus.

When someone with RSV coughs or sneezes, a nearby person can get the virus by breathing in or touching droplets in the air that have the virus.

What are the symptoms of RSV infection?

Children usually get symptoms like runny nose, fever, cough, and wheeze (a whistling sound when breathing).

In older children and adults, symptoms usually aren't serious.

However, in babies, symptoms can be severe. In babies younger than 6 months old, the first symptom may be a temporary stop in breathing (apnea). Sometimes young babies have serious breathing problems with severe wheezing and low oxygen levels in their blood.

How can doctors tell if my child has RSV?

There are many viruses that cause the same symptoms as RSV, and doctors don't always need to tell them apart. But if they do, doctors test samples of mucus from the nose.

How do doctors treat RSV?

Most children get well at home with rest and fluids. If they have trouble breathing, doctors treat them in a hospital with oxygen. Nebulizers with medicine that stops the wheezing and asthma don't help much with the wheezing and RSV infection.

How do doctors prevent RSV?

There is no vaccine to prevent RSV.

People with young children should wash their hands a lot to keep from passing on the virus.

Rarely, doctors give monthly shots of medicine that can make RSV infection less severe. They use this medicine only in children who are most likely to have serious breathing problems from RSV, for example, young children who have serious heart or lung disease or those who were born very premature.