Sustained Declines in Age Group-Specific Rotavirus Infection and Acute Gastroenteritis in Vaccinated and Unvaccinated Individuals During the 5 Years Since Rotavirus Vaccine Introduction in England.

BACKGROUND: The introduction of an oral live-attenuated monovalent rotavirus vaccine (Rotarix®) into the UK infant immunization program in July 2013 was associated with large reductions in laboratory-confirmed rotavirus infections and hospitalizations due to acute gastroenteritis (AGE) within 12 months. Here we report the 5-year impact of the program in England. METHODS: Individuals with laboratory-confirmed rotavirus infections during 2000-2018 and all-cause hospitalizations for AGE during 2007-2018 were identified using national electronic records. Age-specific incidence rate ratios (IRR) and estimated numbers of cases averted in each of the 5 postvaccination years were calculated. RESULTS: There were 206 389 laboratory-confirmed rotavirus infections and 3 657 651 hospitalizations for all-cause AGE. Reductions of 69-83% in laboratory-confirmed rotavirus infections in all age groups and 77-88% in infants aged <1 year in each of the 5 postvaccine years are reported, with 11 386-11 633 cases averted annually. All-cause AGE hospitalizations were reduced by 12-35% across all age-groups and by 25-48% in <1 year-olds in the 5 postvaccine years, with 24 474-49 278 hospitalizations averted annually. There was strong evidence of indirect (herd) protection, with at least 50% and up to 80% of the non-specific end point of all-cause gastroenteritis (AGE) hospitalizations averted being in unvaccinated age-groups, primarily older adults. Seasonal changes include a possible shift from annual to biennial peaks with lower peak incidence and longer seasons. CONCLUSIONS: There were large and sustained declines in both laboratory-confirmed rotavirus infections and AGE hospitalizations across all age groups in each of the 5 years since the introduction of the UK rotavirus program.