Kamigaki Taro, Oshitani Hitoshi
Department of Virology, Tohoku University Graduate School of Medicine.
PLoS Curr. 2009 Dec 20;1:RRN1139. doi: 10.1371/currents.RRN1139.
Pandemic (H1N1) 2009 has been causing large outbreaks in Japan. Yet, the case fatality rate (CFR) remains low and only 85 deaths have been confirmed as of December 17, 2009. Surveillance data was analyzed to define epidemiological characteristics of pandemic (H1N1) 2009 in Japan. It was shown that most of the reported influenza-like illness cases and hospitalizations have occurred in those aged 5-9 years and 10-14 years, in whom CFR is extremely low. However, CFRs are higher in small children (<5 years) and adults. The transmission to these age groups may possibly have been minimized through aggressive suspension of classes in schools.
2009年甲型H1N1流感大流行在日本引发了大规模疫情。然而，病死率仍然很低，截至2009年12月17日，仅确认有85人死亡。对监测数据进行了分析，以确定2009年甲型H1N1流感大流行在日本的流行病学特征。结果显示，报告的大多数流感样疾病病例和住院病例发生在5至9岁和10至14岁的人群中，这些人群的病死率极低。然而，年幼儿童（<5岁）和成年人的病死率较高。通过在学校积极停课，可能已将向这些年龄组的传播降至最低。
