Article ID: JJID.2016.052
Variable incidence rates of rotavirus gastroenteritis hospitalizations were reported in Japan. However, it is not known whether the observed regional differences were due to the real difference in the occurrence of severe disease or other causes. This study aimed at determining the incidence rates of rotavirus hospitalizations among children age <5 years in the Yuri district in Akita prefecture and the Nantan district in Kyoto prefecture between March 2012 and February 2013 (during which the rotavirus vaccine uptake rates were equally very low) by using the standardized case definition, severity scores, and the same assays on the specimens. There were 44 rotavirus cases (44%) among 101 acute gastroenteritis hospitalizations in the Yuri district with a catchment population of 3,853, and 18 rotavirus cases (47%) among 38 acute gastroenteritis hospitalizations in the Nantan district with a catchment population of 5,128. While severity scores at the time of hospitalizations were 11 in both hospitals, the incidence rates in Akita and Kyoto were 11.7 (95% confidence interval [CI]: 8.5-15.6) and 3.9 (95%CI: 2.1-5.5) per 1000 child-years, respectively. Thus, there was real difference in the occurrence of severe rotavirus disease between the two regions.
