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Respiratory Syncytial Virus

Medically reviewed by Last updated on Jan 5, 2022.

What is Respiratory Syncytial Virus?

Harvard Health Publishing

Respiratory syncytial virus (RSV) is one of the many viruses that cause the common cold and infections in the upper parts of the respiratory tract. RSV also can cause infection in the lower respiratory tract, such as pneumonia in the lung tissue and bronchiolitis inside the smallest airways (bronchioles) in the lungs.  

RSV is spread in secretions when someone with it coughs or sneezes. RSV also can be carried on unwashed hands and on contaminated objects, such as dirty tissues, doorknobs and desk tops. It typically enters the body through the eyes, nose or mouth when someone with contaminated fingers touches his or her face or eyes or breathes in droplets.  

People who have the greatest risk of serious illness from RSV include: 

  • Infants, especially those who were born early (premature) 
  • The elderly 
  • People of any age with certain types of heart disease, chronic lung disease or weakened immune systems 

The highest rates of serious childhood RSV illness occur in infants under 6 months old. Almost all children have been exposed to RSV by the age of 2. Most do not become dangerously ill. Getting RSV more than once can happen, but infections that follow the first one generally are mild. 


RSV tends to cause typical cold symptoms, including:  

In general, the symptoms caused by RSV tend to be more severe than the average common cold. Symptoms generally begin within a week after an exposure to someone with an RSV infection.  

In infants and children younger than age 3, or older children with underlying lung, heart or immune problems, RSV may start out looking like a mild cold with sneezing and runny nose. After two or three days, RSV can spread into the chest, causing a cough, breathing that is faster than normal and wheezing. Young children also can have a high fever. Infants with breathing difficulties may grunt; flare the nostrils; or have "retractions," which means the chest muscles are drawn in so that the ribs can be seen as the baby struggles to breathe. 


Your doctor may suspect an RSV infection based on the symptoms and a physical examination during certain times of the year when RSV is most common. In most adults and older children, further testing is unnecessary because RSV symptoms generally are mild, and the illness usually is treated at home.  

When examining infants and children younger than age 3, or children with underlying lung, heart or immune problems, the doctor will check for fever, cough, nasal discharge that may interfere with feeding, the chest drawing in, wheezing, breathing quickly, and a bluish color to the lips and fingernails. If your child's symptoms are severe or not as expected, the doctor may want to confirm the diagnosis of RSV infection by taking a sample of nose or throat secretions to test for the virus in a laboratory. 

Expected Duration

In people who are basically healthy, RSV infection typically lasts about one to two weeks. The wheezing that is caused by RSV, however, can last a month or longer.


Preventing RSV is difficult because the virus is highly contagious and is spread easily from person to person. The best way to prevent RSV infection is to wash hands regularly, especially when someone in the family has cold symptoms. Adults and older children should always wash their hands frequently, avoid touching their face and eyes unnecessarily, and stay away from direct contact with people who have obvious cold symptoms. Young infants should be kept away from anyone who has symptoms of a respiratory infection, even if it's just a slight cold.  

Babies who were born prematurely or those with lung problems, congenital heart disease or problems with their immune systems have a higher chance of getting a serious RSV infection. For these babies, a medication called palivizumab (Synagis) is often recommended. It is given once a month as a shot in the muscle from just before RSV season (November) to the end of it (April). 


For mild RSV infections, treatment is aimed at making the person comfortable. Treatment may include:  

  • Something for fever and pain -- for example, acetaminophen (Tylenol and others) or ibuprofen (Advil and others)  
  • Drinking lots of fluids to prevent dehydration  
  • Bed rest  
  • A humidifier to soothe the throat and nose and possibly relieve cough  
  • Saline (salt water) nose drops  
  • A bulb syringe to gently loosen mucus blocking a child's or infant's nose  

Infants and younger children with severe RSV infection may need to be hospitalized. In the hospital, the infant or child may receive oxygen, fluids (by vein) and medications to help him or her breathe easier.  Certain patients with weakened immune systems may be given a medication called ribavirin

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

When To Call a Professional

Call your doctor immediately if your infant or younger child has:  

  • A high fever 
  • Severe cough 
  • Wheezing 
  • Difficulty feeding 
  • Difficulty breathing 
  • Abnormally fast breathing 
  • Grunting 
  • Flaring of the nostrils 
  • Chest retractions 
  • Bluish lips or fingernails  

If you have a premature infant or one with serious respiratory or other health problems, speak to your doctor about your baby's need for preventive medicines from late fall through early spring. 


Most RSV infections go away completely with no lasting effects. With prompt diagnosis and appropriate treatment, most infants and children recover from serious respiratory illnesses caused by RSV infections. Deaths from RSV infections are relatively rare, but RSV infection can cause death in high-risk infants aged 2 months to 6 months and in older people who have immune system problems. Children who have RSV bronchiolitis in infancy have a slightly higher risk of having recurrent wheezing as they get older. It's not known if RSV causes this, or whether children who are at higher risk of asthma are more likely to become ill with RSV exposure during infancy.

Additional Info

Centers for Disease Control and Prevention (CDC) 

Learn more about Respiratory Syncytial Virus

Treatment options

Care guides

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.