Characteristics analysis on the first epidemic of influenza A(H1N1)in Wenzhou

Abstract

Objective To analyse the epidemiological characteristics of the first influenza A (H1N1) epidemic in Wenzhou and provide a scientific basis for the measures on control and prevention of influenza. Methods A descriptive epidemiological method was used for analysis of influenza A (H1N1) case data in Wenzhou from May 2009 to July 2010. Results There were 4164 cases (accumulative incidence 53.94/100 000) of influenza A (H1N1) in Wenzhou between May 2009 and July 2010. The peak of incidence was from October 2009 to January 2010, there were 3825 cases, accounted for 91.86%. The patients occurred in eleven counties(districts) of Wenzhou. Most of the cases were found in Lucheng, Ruian and Yueqing counties (districts). Cases for groups aged 5-19 years accounted for 67.39% (2806 The influenza A (H1N1) is gradually transmitted from urbans to rural areas after first imported case is introduced to Wenzhou. The incidence rate is closely related to density of population and mobility of population. Schools are risk sellings for transmissions of influenza A (H1N1). It is very critical to strengthen the epidemiological surveillance for influenza in schools. The influenza A (H1N1) vaccination is specific measures for the prevention of influenza A(H1N1) and gained apparent effectiveness. Key words: Influenza A virus, H1N1 subtype; Epidemiologic characteristics; Intervening measures