Respiratory Syncytial Virus (RSV)


Respiratory Syncytial Virus (RSV) is a contagious viral disease that is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia in children under one year of age in the United States. Almost all children will have had an RSV infection by their second birthday. Of the infants and children exposed to RSV for the first time, 25 to 40 percent of them have signs or symptoms of bronchiolitis or pneumonia. However, only 0.5 to 2 percent will actually require hospitalization. Most children that do require hospitalization are under six months of age.

Premature infants, children under two years of age who have congenital heart or chronic lung disease, or children with a weakened immune system are at highest risk for developing severe disease. People of any age can develop an infection from RSV. However, when infections occur later in life, it is less severe. Adults at high risk for developing severe RSV disease include the elderly, adults with chronic heart or lung disease, or those with a weakened immune system.

RSV infection typically occurs in the fall, peaks in the winter and then goes down in the early spring. However, the exact timing of RSV season varies by geographic location.


RSV spreads when someone who is infected coughs or sneezes. This causes respiratory droplets to spread into the air. The droplets that contain RSV can end up in someone’s nose or mouth and lead to infection. In addition, those droplets could also land on objects people touch, such as countertops or toys. People can be exposed to and possibly infected by RSV by touching those objects and then touching their mouth or nose. Children commonly pass the virus to one another at their school or daycare center.


RSV symptoms are like those of many other respiratory illnesses and usually begin four to six days after exposure to the virus. Typically, fever, sneezing, coughing and wheezing develop one to three days later. In very young infants, the only symptoms of infection may include irritability, decreased activity and breathing difficulties. If infants are otherwise healthy, they usually do not require hospitalization. Those infants who have severe cases and are hospitalized may require oxygen, suctioning of mucus from the airways or intubation with mechanical ventilation. Often, infants improve with supportive care and are discharged in a few days.

RSV infections may also occur in older children and adults. Symptoms usually include runny nose, sore throat, headache, cough and a feeling of general sickness. The disease usually lasts fewer than five days, however, some high-risk adults may have more serious symptoms that are similar to a lower respiratory tract infection like pneumonia.


There are different types of laboratory tests available for the diagnosis of RSV infection:

  • Antigen detection
    • Respiratory secretions are tested for presence of the virus. This test is generally reliable in young children but less useful in older children and adults.
  • RT-PCR assay
    • This test detects and measures the amount of virus in the body and is often used when testing older children and adults.
  • Serologic
    • The antibodies that develop to fight RSV are measured with this test. It is not used for routine diagnosis, but to monitor how often RSV is occurring in a specific geographic location.


Specialty drug list

There is no specific treatment or vaccine for RSV. However, for infants and children at high risk, a drug called Synagis® (palivizumab) is available to prevent the development of serious RSV disease. It cannot cure or help treat children already suffering from serious RSV disease and cannot prevent infection with RSV.

Side Effects

The most common side effects of Synagis® (palivizumab) are upper respiratory tract infection, otitis media, fever, rhinitis, rash, diarrhea, cough and vomiting.


There are many resources and organizations available to help, providing support, advocacy and information: