Analysis on the Epidemic Characteristics of H1N1 Influenza in Qinghai in 2009—2010

Objectives To analyze the incidence of H1N1 influenza in Qinghai in 2009-2010.

Methods The data on the surveillance of etiology and epidemiology of H1N1 influenza collected from the "China information system for surveillance of influenza " were analyzed with the data from the Sixth National Census by Excel 2003.

Results The peak incidence was in September-October in 2009 and the diagnosis of 2 034 H1N1 influenza cases was confirmed. The standardized incidence of H1N1 influenza in Xining was 84.8/10⁶, the highest rate in Qinghai Province. The incidence in male was higher than that in female (χ² = 1190.9150, P < 0.0001). The incidence was decreased with the age increased (χ² = 36.5890, P < 0.0001).

Conclusions The peak incidence of H1N1 influenza was appeared in September in 2009, earlier than the usual seasonal flu in the past. The incidence of males was higher than females, the incidence decreased with the increase of age.