Effectiveness of the pentavalent rotavirus vaccine in preventing gastroenteritis in the United States.

OBJECTIVE: In clinical trials, the pentavalent rotavirus vaccine (RV5) was efficacious in preventing severe rotavirus gastroenteritis (RGE) and related health care encounters. We assessed the vaccine effectiveness (VE) of RV5 among US infants during the first 2 rotavirus seasons after vaccine licensure.

METHODS: Using a large, national, health insurance claim database, we monitored 2 cohorts of infants (infants who received 3 doses of RV5 and a concurrent group of infants who received 3 doses of diphtheria-tetanus-acellular pertussis vaccine but did not receive RV5) through the 2007 and 2008 rotavirus seasons (January 1 to May 31), to identify cases of RGE and all-cause acute gastroenteritis (AGE) resulting in medical care encounters. We estimated the VE in reducing hospitalizations, emergency department (ED) and physician office visits, and health care resource utilization, as measured by days and costs of hospitalizations and ED visits.

RESULTS: A total of 33 140 RV5-vaccinated infants and 26 167 infants in the concurrent diphtheria-tetanus-acellular pertussis vaccine cohort were included in the analysis. The VE against RGE (hospitalization and ED) was 100% (95% confidence interval [CI]: 87%-100%), whereas the VE against AGE was 59% (95% CI: 47%-68%). In the outpatient setting, the VE against RGE and AGE was 96% (95% CI: 76%-100%) and 28% (95% CI: 22%-33%), respectively. There was a complete (100%) reduction in RGE hospitalization and ED visit days and a 100% reduction in costs. RV5 was associated with a 66% decrease in AGE-related hospitalization and ED visit days and a 74% reduction in costs.

CONCLUSIONS: In this first nationwide study evaluating VE under conditions of routine use, RV5 was highly effective in preventing RGE and AGE and in reducing health care resource utilization. Further research is needed to assess VE with an incomplete rotavirus vaccination regimen.