Respiratory syncytial virus

Respiratory syncytial virus infection and human metapneumovirus infection cause upper and sometimes lower respiratory tract infections.

• Respiratory syncytial virus is a very common cause of respiratory infections in infants and young children.
• Human metapneumovirus is similar to respiratory syncytial virus but is a separate virus.
• Typical symptoms include a runny nose, fever, cough, and wheezing, and a severe infection can lead to respiratory distress.
• The diagnosis is based on symptoms and their occurrence at expected times of year.
• Palivizumab is given to children at high risk of developing a severe respiratory syncytial virus infection.
• Oxygen is given as needed.

Respiratory syncytial virus (RSV) is a very common cause of respiratory tract infection, particularly in children. Nearly all children have been infected by age 4 years, many in the first year of life. Infection does not provide complete immunity, so reinfection is common, although usually less serious. Outbreaks typically occur in winter and early spring. RSV is the most common cause of lower respiratory tract illness in young infants and is responsible for more than 50,000 hospitalizations every year in the United States in children under the age of 5 years.

The first infection often progresses from an upper respiratory tract illness with congestion and fever to involve the lower respiratory tract, most commonly causing bronchiolitis and sometimes pneumonia with cough and difficulty breathing. Later infections usually involve only the upper respiratory tract. Children who have had bronchiolitis are more likely to be diagnosed with asthma when they are older.

Children with serious underlying disorders (such as congenital heart disease, asthma, cystic fibrosis, or immune system suppression) or who were born prematurely, and infants under 3 months of age are at particular risk of developing serious illness. Adults and older children also can be infected with RSV, and the elderly may develop pneumonia.