By age 2, most children will have been infected with respiratory syncytial virus. Children who attend child care centers or who have siblings who attend school are at a higher risk of exposure. So are infants who are exposed to high levels of air pollution or cigarette smoke. Susceptibility is also greater during the peak RSV season, which typically begins in the fall and ends in the spring.

People at increased risk of severe — sometimes life-threatening — infections include:

  • Infants younger than 6 months of age
  • Younger children, especially under 1 year of age, who were born prematurely or who have an underlying condition, such as congenital heart or lung disease
  • Children with weakened immune systems, such as those undergoing chemotherapy or transplantation
  • Older adults
  • Adults with asthma, congestive heart failure or chronic obstructive pulmonary disease
  • People with immunodeficiency, including those with certain transplanted organs, leukemia or HIV/AIDS
Jul. 29, 2011