Respiratory syncytial virus (RSV)

Alternative names

Respiratory syncytial virus (RSV) is a very common virus that causes mild cold-like symptoms in adults and older healthy children. It can cause serious respiratory infections in young babies, especially those born prematurely, who have heart or lung disease, or who are immunocompromised.

Causes, incidence, and risk factors

RSV is the most common respiratory pathogen in infants and young children. It has infected nearly all infants by the age of two years. Seasonal outbreaks of acute respiratory illness occur each year, on a schedule that is somewhat predictable in each region. The season typically begins in the fall and runs into the spring.

RSV is spread easily by physical contact. Touching, kissing, and shaking hands with an infected person can spread RSV. Transmission is usually by contact with contaminated secretions, which may involve tiny droplets or objects that droplets have touched. RSV can live for half an hour or more on hands. The virus can also live up to five hours on countertops and for several hours on used tissues. RSV often spreads very rapidly in crowded households and day care centers.

In infants and young children, RSV can cause Pneumonia, bronchiolitis (inflammation of the small airways of the lungs), and tracheobronchitis (croup). In healthy adults and older children, RSV is usually a mild respiratory illness. Although studies have shown that people produce Antibody against the virus, infections continue to occur in people of all ages.

Each year up to 125,000 infants are hospitalized due to severe RSV disease; and about 1-2% of these infants die. Infants born prematurely, those with chronic lung disease, those who are immunocompromised, and those with certain forms of heart disease are at increased risk for severe RSV disease. Those who are exposed to tobacco smoke, who attend daycare, who live in crowded conditions, or have school-age siblings are also at higher risk.


  • Nasal congestion  
  • nasal flaring  
  • cough  
  • Rapid breathing (tachypnea)  
  • breathing difficulty or labored breathing  
  • Shortness of breath  
  • cyanosis (bluish discoloration of skin caused by lack of oxygen)  
  • wheezing  
  • fever  
  • croupy cough (often described as a “seal bark” cough)

Note: Symptoms are variable and differ with age. Infants less than one year old are most severely affected and often have the most trouble breathing. Older children usually have only mild, cold-like symptoms. Symptoms usually appear 4-6 days after exposure.

Signs and tests
Rapid tests for this virus can be performed at many hospitals on fluid obtained from the nose. Listening to the chest with a stethoscope (auscultation) may reveal wheezes or other abnormal lung sounds.

Tests used in the diagnosis of RSV include:

  • a Chest x-ray (may show pneumonia or bronchiolitis)  
  • arterial blood gas analysis (demonstrates decreased oxygen saturation)

Antibiotics do not help in the treatment of RSV. Mild infections resolve without treatment. A severe infection in infants and children may require hospitalization to provide supplemental oxygen, humidified air, and hydration by intravenous fluids. Respiratory support may be needed, using a breathing machine (ventilator).

Your doctor will be the best judge as to what treatment to use. A medication to open the airways of the lungs (bronchodilator) is sometimes used. In some instances, an antiviral medication such as Ribavirin is occasionally used.

Expectations (prognosis)
RSV infection may rarely cause death in infants, but this is unlikely if the child is seen early in the course of the illness. In older children and adults, the disease will usually be quite mild. There is evidence suggesting an increased incidence of Asthma in children who have developed RSV bronchiolitis. It is unknown whether the factors that predispose the child to asthma also predisposed him to developing bronchiolitis as an infant, or if the RSV bronchiolitis itself predisposes the child to develop Asthma later.


  • ear infections  
  • Pneumonia  
  • respiratory failure

Calling your health care provider

Call your health care provider if breathing difficulties or other symptoms of this disorder appear. Any breathing difficulties in an infant should be regarded as an emergency and the appropriate help sought.


A simple way to help prevent RSV infection is to wash your hands often, especially before touching your baby. It’s important to make certain that other people, especially care givers, take precautions to avoid giving RSV to your baby. The following simple steps can help protect your baby:

  • Insist that others wash their hands with warm water and soap before touching your baby.  
  • Have others avoid contact with the baby if they have a cold or fever. If necessary, it may be helpful to wear a mask.  
  • Be aware that kissing the baby can spread RSV infection.  
  • Try to keep young children away from your baby. RSV is very common among young children and is easily spread from child to child.  
  • Do not smoke near your baby. Exposure to tobacco smoke increases the risk of RSV illness.

Parents with high-risk young infants should avoid crowds during outbreaks of RSV. Moderate-to-large outbreaks are often reported in the local news and newspapers to provide parents with an opportunity to avoid exposure.

Additionally, an important product is available to prevent RSV infection: Synagis (palivizumab). It has been approved for prevention of RSV disease in children younger than 24 months of age who are at high risk for serious RSV disease. Synagis has not been approved for treatment of RSV infection, making prevention for high-risk children even more important. Synagis is given as a monthly shot to protect your child from contracting RSV. If your child is in a high-risk group, ask your doctor about using a preventive medicine.

Johns Hopkins patient information

Last revised: December 4, 2012
by Amalia K. Gagarina, M.S., R.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.