What Is Respiratory Syncytial Virus?

Respiratory syncytial (sin-SISH-ul) virus (RSV) is a major cause of respiratory illness in young children. The virus infects the lungs and breathing passages.

What Are the Signs & Symptoms of Respiratory Syncytial Virus?

Kids with RSV might have cold symptoms, such as:

RSV infections in premature babies, infants, and kids with diseases that affect the lungs, heart, or immune system, can lead to other, more serious illnesses such as pneumonia or bronchiolitis.

Is Respiratory Syncytial Virus Contagious?

Respiratory syncytial virus is highly contagious. It spreads through droplets containing the virus when someone coughs or sneezes. It also can live on surfaces (like counters or doorknobs) and on hands and clothing. So people can get it if they touch something that's contaminated.

RSV can spread quickly through schools and childcare centers. Babies often get it when older kids carry the virus home from school and pass it to them. Almost all kids have had RSV at least once by the time they're 2 years old.

RSV infections often happen in epidemics that last from late fall through early spring. Respiratory illness caused by RSV — such as bronchiolitis or pneumonia — usually lasts about a week, but some cases may last several weeks.

How Is Respiratory Syncytial Virus Diagnosed?

Doctors usually diagnose respiratory syncytial virus by taking a medical history and doing an exam. In most healthy kids, they don't need to distinguish RSV from a common cold.

But if a child has other health conditions, the doctor might want to make a specific RSV diagnosis. In that case, the virus is identified by testing nasal fluids. The sample is collected either with a cotton swab or by suction through a bulb syringe.

How Is Respiratory Syncytial Virus Treated?

Most cases of respiratory syncytial virus are mild and don't need medical treatment from doctors. Antibiotics aren't used because RSV is a virus and antibiotics work only against bacteria. Sometimes, doctors give medicine to help open airways.

RSV infection can be more serious in babies, though. Some might need treatment in a hospital. There, they can be watched closely and get fluids, if needed, and treatment for any breathing problems.

Home Care

At home:

  • Make your child as comfortable as possible.
  • Allow time for recovery.
  • Provide plenty of fluids. Babies may not feel like drinking, so offer fluids in small amounts often.

Avoid hot-water and steam humidifiers, which can be hazardous and can cause scalding. If you use a cool-mist humidifier, clean it daily with household bleach to prevent mold and bacteria growth.

If your child is uncomfortable and too young to blow his or her own nose, use a nasal aspirator (or bulb syringe) to remove sticky nasal fluids.

Treat fever using a non-aspirin fever medicine like acetaminophen. Aspirin should not be used in children with viral illnesses. Its use has been linked to Reye syndrome, a life-threatening illness.

Can Respiratory Syncytial Virus Be Prevented?

Because RSV can be easily spread by touching infected people or surfaces, washing hands well and often is key in stopping it. Wash your hands after being around someone who has cold symptoms. And school-age kids who have a cold should keep away from younger siblings — especially babies — until their symptoms pass.

To prevent serious RSV-related respiratory disease, at-risk infants can get a monthly injection of a medicine with RSV antibodies during peak RSV season (roughly November to April). The protection it gives is short-lived, though. So they'll need injections each RSV season until they're no longer at high risk for severe RSV infection. Ask the doctor if your child is considered high risk.

When Should I Call the Doctor?

Call the doctor if your child has:

  • a high fever and doesn't look well
  • a thick nasal discharge
  • a cough that gets worse or produces yellow, green, or gray mucus
  • signs of dehydration

Also call the doctor if your infant is very cranky, or refuses to breastfeed or bottle-feed.

Get medical help right away if your child:

  • has trouble breathing or is breathing very rapidly
  • is very drowsy
  • has lips or fingernails that look blue
Back to Articles

Related Articles

Germs: Bacteria, Viruses, Fungi, and Protozoa

Germs are the microscopic bacteria, viruses, fungi, and protozoa that can cause disease.

Read More

Is It a Cold, the Flu, or COVID-19?

Your child has a sore throat, cough, and a high fever. Is it COVID-19? Could it be the flu? Or just a cold? Here are tips on what to look for, and what to do.

Read More

Hand Washing: Why It's So Important

Washing your hands well and often is the best way to keep from getting sick. Here's how to teach this all-important habit to your kids.

Read More


Coughs are a common symptom, but most aren't a sign of a serious condition. Learn about different coughs, how to help your child feel better, and when to call your doctor.

Read More


Pneumonia is a lung infection that can be caused by different types of germs, most commonly viruses. Read about symptoms and treatment.

Read More


Sinus infections, or sinusitis, are common and easily treated.

Read More


Bronchiolitis is a common illness of the respiratory tract caused by an infection that affects tiny airways. The best treatment for most kids with bronchiolitis is time to recover and plenty of fluids.

Read More


Colds are the most common infectious disease in the United States - and the top reason kids visit the doctor and miss school.

Read More

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.