A Retrospective Evaluation of Hospitalizations for Acute Gastroenteritis at 2 Sentinel Hospitals in Central Japan to Estimate the Health Burden of Rotavirus

Background. Two rotavirus vaccines have recently been licensed for use in >80 countries worldwide but not in Japan. To assess the value of introducing rotavirus vaccination in Japan, data on the burden of rotavirus disease are needed. Methods. To describe the epidemiology of severe rotavirus disease among Japanese children aged <5 years, we examined retrospective demographic, clinical, and laboratory data from the period 2003-2007 for children hospitalized with acute gastroenteritis (AGE) at 2 sentinel hospitals in Japan. Results. At each of the 2 hospitals, 17%-21% of all pediatric hospitalizations were for AGE. Three-fourths of all AGE-related admissions occurred during the winter (December-May). Rotavirus testing was performed for approximately three-fourths of patients admitted with AGE in the winter, of which 55% at one hospital and 59% at the other tested positive. By extrapolating the test results to those patients with AGE admitted in the winter who were not tested, we estimated that 39%-44% of year-round and 52%-57% of winter hospitalizations were attributable to rotavirus. The annual incidence of hospitalization for rotavirus AGE in the 2 cities served by the hospitals was estimated to be 3.8 and 4.9 per 1000 person-years. Conclusions. The burden of severe rotavirus disease among Japanese children is substantial and warrants consideration of vaccination as a prevention strategy.