Infant rotavirus immunization was found to result in long-term, population-level effects as demonstrated by decreased incidence of hospitalizations for rotavirus-specific gastroenteritis (RVGE) across all groups, as reported by a study published in Clinical Infectious Diseases.
Investigators obtained data from the Healthcare Cost and Utilization Project State Inpatient Database to analyze monthly hospital discharge rates for all-cause acute gastroenteritis (AGE) and RVGE from January 2000 to December 2013. Patients included in the study were analyzed separately according to the following age groups: 0 to 4 years, 5 to 19 years, 20 to 59 years, and ≥60 years. A total of 13,527,516 cases of hospitalizations associated with AGE were identified, 224,099 (1.7%) of which were RVGE specific.
Vaccination impact was measured by comparing AGE and RVGE age-specific hospitalization rates prior to and after vaccine introduction. Monthly pre-vaccine rates overall (2000-2006) were compared to monthly post-vaccine rates overall (2008-2013), monthly post-vaccine rates for even (2008, 2010, 2012) and odd post-vaccine calendar years (2009, 2011, 2013) separately to assess potential biennial patterns, and monthly post-vaccine rates for each individual calendar year.
The highest rate of AGE hospitalizations was seen in those aged ≥60 years (monthly rate, 10.2 hospitalizations per 10,000 age-specific population [pre-vaccine] to 15.7 hospitalizations [post-vaccine]). An increasing trend was identified among those aged 20 to 59 years; no evidence was found for an increase in those aged 0 to 4 years or 5 to 19 years. AGE hospitalization rates for those aged 0 to 4 years were reduced in the post-vaccine period compared with the pre-vaccine period (risk ratio [RR], 0.54), with greater reductions found in even years vs odd years (even year RR, 0.50; odd year RR, 0.58). No reductions in hospitalization rates were observed for the 20- to 59-years or ≥60-years age groups.
Rates of hospitalization for RVGE decreased among all age groups, with the 0- to 4-year age group experiencing the most significant decrease at >85%. Larger declines occurred in even years (RR, 0.10) compared with odd years (RR, 0.20). Among those ≥60 years, the ratio of post-vaccine to pre-vaccine hospitalization rates declined (RR, 0.76), with significant declines seen in the even years (RR, 0.51); no change was found in odd years for this age group.
“Rotavirus vaccination had a substantial impact on RVGE hospitalizations across age groups during the six year period, highlighting the role of infants as drivers of infection transmission,” the authors concluded. ”Overall reductions in the incidence of RVGE hospitalizations were observed for children, adolescents, and adults during the post-vaccine period with diminished direct impacts as age group increased.”
Baker JM, Tate JE, Steiner CA, Haber MJ, Parashar UD, Lopman BA. Longer-term direct and indirect effects of infant rotavirus vaccination across all ages in the US; 2000 – 2013: analysis of a large hospital discharge dataset [published online July 18, 2018]. Clin Infect Dis. doi: 10.1093/cid/ciy580