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Respiratory syncytial (sin-SISH-uhl) virus, or RSV, is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious, especially for infants and older adults. In fact, RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) in children younger than 1 year of age in the United States. It is also a significant cause of respiratory illness in older adults.

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Fast Facts

Baby girl
  • Almost all children will be infected with RSV by their second birthday.
  • RSV usually causes mild respiratory illness, but it can be serious, especially in infants and older adults.
  • RSV is the most common cause of bronchiolitis and pneumonia in children younger than 1 year of age.
  • In the U.S., RSV infections generally occur during fall, winter, and spring.

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CDC Featured Podcast

Podcast

Dr. Eileen Schneider talks about RSV, a common cause of respiratory illness in young children.

Listen To This Podcast (4:22)

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