About RSV

What to know

  • RSV is a common respiratory virus that usually causes mild, cold-like symptoms.
  • Infants and older adults are more likely to develop severe RSV and need hospitalization.
  • CDC recommends immunizations to protect infants, some young children, and older adults.
Grandfather holding baby

What is RSV?

Respiratory syncytial (sin-SISH-uhl) virus, or RSV, is a common respiratory virus that infects the lungs, but can also affect the nose and throat. RSV spreads in the fall and winter along with other respiratory viruses, like flu and COVID-19. It usually peaks in December and January.

Did you know?‎

RSV was discovered in 1956 by scientists at Walter Reed Army Institute for Research in Washington, D.C.

RSV symptoms make it difficult to distinguish it from the common cold or other respiratory viruses (like the flu or COVID-19). Most people that get RSV will only have mild illness, but it can be very dangerous for babies, young children and adults 60 and older.

RSV can be dangerous for infants and older adults

RSV can also cause more severe infections such as bronchiolitis (an inflammation of the small airways in the lungs) and pneumonia (an infection of the lungs). It is the most common cause of bronchiolitis and pneumonia in children younger than 1 year of age.

RSV does not usually cause severe illness in healthy adults and children. However, some people with RSV infection, especially older adults and infants younger than 6 months of age, may need to be hospitalized.

In the most severe cases, a person may require additional oxygen, IV fluids if they can't eat or drink enough, or intubation (have a breathing tube inserted through the mouth and down to the airway) with mechanical ventilation (a machine to help a person breathe). In most of these cases, hospitalization only lasts a few days.

Learn more about people at high risk for severe RSV infection.