Respiratory syncytial virus (RSV) is a virus that causes respiratory infections. It is the most common cause of bronchiolitis (inflammation of the bronchioles within the lungs) and pneumonia
among infants and children under one year of age.
Up to 126,300 children are hospitalized annually in the United States for bronchiolitis or pneumonia. Annual RSV outbreaks peak in February, and account for one fourth to one third of all pediatric hospitalizations for pneumonia and one half of the hospitalizations for bronchiolitis.
This virus is very contagious. It is believed that by the age of three, almost all children will have had an RSV infection. Fortunately, in most cases, the infection is not serious.
A person is most contagious during the first two to four days of their symptoms.
The virus is spread from respiratory secretions, through close contact with infected people, or contact with contaminated surfaces or objects. Infection can occur when infectious material comes into contact with mucous membranes of the eyes, mouth, or nose, and possibly through the inhalation of droplets generated by a sneeze or cough.