Last reviewed 01/2018

An estimated 2.1 million children younger than 5 years require medical attention annually for an RSV infection.

  • it can occur and recur at any age
  • by two years of age, nearly all children have been infected by RSV at least once (1)

Out breaks are usually caused by two subtypes, A and B.

  • subtype A is usually responsible for more severe disease
  • dominant strains shift each year resulting in frequent reinfections (1)

Infection may occur at any time but is least frequent in the summer, accounting for 20 to 25% of hospital admissions for pneumonia of young infants and children and for 75% of cases of bronchiolitis in this age group

  • RSV infection is a clearly identified winter virus usually occurring in the UK within the period October to March with most infections occurring in a relatively short epidemic of about six weeks (2)