Infant Rotavirus Vaccination Provides Indirect Protection to Older Children and Adults

Background:  Rotavirus vaccination was introduced as part of the routine vaccination schedule in U.S. infants following the recommendation Advisory Committee on Immunization Practices in 2006.  The vaccine led to a rapid and substantial impact on rotavirus epidemiology and burden of disease in U.S. children. 

Objectives: To determine whether indirect protection of rotavirus vaccination is afforded to older children, adults and the elderly.

Methods: We used nationally-representative administrative data on hospitalizations in the U.S. population, including all ages, hospitalized for rotavirus or cause-unspecified gastroenteritis from 2000 to 2008. Poisson regression models were fitted, controlling for background secular trends and seasonal variation. The rate ratio of rotavirus and cause-unspecified gastroenteritis hospitalizations in 2008 was compared with the pre-vaccine era (2000 to 2006), by age and demographic characteristics. 

Results:  Rotavirus hospital discharges decreased in 2008 in all ages groups, with statistically significant reductions in 0-4, 5-14 and 15-24 year age groups (rate ratio (RR), p-value (p) = 0.22, <0.0001; 0.29, <0.0001; 0.35, <0.0001; respectively). In these same age groups, there were statistically significant reduction in cause-unspecified gastroenteritis discharges (RR, p = 0.61, <0.0001; 0.71, <0.0001; 0.92, 0.01; respectively), with signification reductions observed in March, the historic peak rotavirus month, in all age groups. Reductions were observed in all demographic strata, but were most pronounced in Hispanics with significant reductions in 2008 across all age groups in this race category (RR, p = 0.66, <0.001). We estimate 10,200 averted hospitalizations in unvaccinated populations aged 5 years and older, representing 15% of the averted hospitalizations and 20% of the averted costs attributable to the vaccination program.

Conclusions: Rotavirus vaccination provides substantial indirect benefits that extend to older children and adults.