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.
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.