title: A two-year surveillance of 2009 pandemic influenza A (H1N1) in Guangzhou, China: from pandemic to seasonal influenza?
abstract: In this two-years surveillance of 2009 pandemic influenza A (H1N1) (pH1N1) in Guangzhou, China, we reported here that the scale and duration of pH1N1 outbreaks, severe disease and fatality rates of pH1N1 patients were significantly lower or shorter in the second epidemic year (May 2010-April 2011) than those in the first epidemic year (May 2009-April 2010) (P<0.05), but similar to those of seasonal influenza (P>0.05). Similar to seasonal influenza, pre-existing chronic pulmonary diseases was a risk factor associated with fatal cases of pH1N1 influenza. Different from seasonal influenza, which occurred in spring/summer seasons annually, pH1N1 influenza mainly occurred in autumn/winter seasons in the first epidemic year, but prolonged to winter/spring season in the second epidemic year. The information suggests a tendency that the epidemics of pH1N1 influenza may probably further shift to spring/summer seasons and become a predominant subtype of seasonal influenza in coming years in Guangzhou, China.
authors: Guangzhou Center for Disease Control and Prevention, Guangzhou, China.
authors: Tiegang
authors: T
authors: Li
authors: Chuanxi
authors: C
authors: Fu
authors: Biao
authors: B
authors: Di
authors: Jibin
authors: J
authors: Wu
authors: Zhicong
authors: Z
authors: Yang
authors: Yulin
authors: Y
authors: Wang
authors: Meixia
authors: M
authors: Li
authors: Jianyun
authors: J
authors: Lu
authors: Yiyun
authors: Y
authors: Chen
authors: Enjie
authors: E
authors: Lu
authors: Jinmei
authors: J
authors: Geng
authors: Wensui
authors: W
authors: Hu
authors: Zhiqiang
authors: Z
authors: Dong
authors: Meng-Feng
authors: MF
authors: Li
authors: Bo-Jian
authors: BJ
authors: Zheng
authors: Kai-Yuan
authors: KY
authors: Cao
authors: Ming
authors: M
authors: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D008875:Middle Aged; D058873:Pandemics; D012621:Seasons; D018571:Sentinel Surveillance; D013997:Time Factors; D055815:Young Adult