Description of hospitalized cases of influenza A(H1N1)pdm09 infection -based on the national hospitalized-case surveillance, 2009-2010, Japan.

This study reports the epidemiological characteristics of hospitalized cases of influenza A(H1N1)pdm09 infection analysed based on the surveillance data collected from 24 July 2009, the date on which the hospital-based surveillance of influenza cases was implemented in Japan, to 5 September 2010. During the study period, a total of 13,581 confirmed cases was reported. Among those cases with information regarding reason for hospitalization, 39% were admitted to hospitals for non-therapeutic purpose such as medical observation and laboratory testing. Overall hospitalization rate was 5.8 cases per 100,000 population when we excluded the cases, whichwere hospitalized for non-therapeutic purposes. While those aged under 20 years accounted for over 85% ofhospitalized cases, the largest proportion of fatal cases was observed in the over 65 years age group. The overall case fatality rate for all hospitalized cases was 1.5%. Year-round surveillance ofhospitalized influenza-like illness cases was launched in 2011 and it was expected that this surveillance system could add value by monitoring changes in epidemiological characteristics of hospitalized cases of seasonal influenza. PMID: 25672359 [PubMed - as supplied by publisher]
Source: Japanese Journal of Infectious Diseases - Category: Infectious Diseases Authors: Tags: Jpn J Infect Dis Source Type: research