Influenza-related excess mortality in Harbin city, 2005-2009

Objective To examine excess mortality related to influenza epidemics in Harbin city from 2005-2009 and to provide reference for influenza control.Methods The population-based mortality data were collected from the disease surveillance system of China Center for Disease Control and Prevention.The meterological data on average temperature and humidity were also collected.Based on rate differential model and Poisson regression model,the numbers of excess mortality related to influenza epidemics from the year of 2005 to 2009 were calculated.Results The duration of influenza prevalence was about 9 weeks in a year from 2005 to 2009.The prevalent influenza strains were H1N1,H3N2,and type B.From 2005-2009,the average influenza-related excess mortality per week was 3/100 000 in Harbin city.Based on rate differential model,the total number of excess death was 15 310 during the 5 years in the city,with the excess deaths of 290,33,1 569,2 988,and 7 184 for the populations of different age of 0,1-14,15-49,50-64,and ≥65 years,respectively.Conclusion The excess mortality resulted from influenza epidemic in Harbin city was high in 2005-2009.The influenza was prevalent about 9 weeks,mainly in winter and spring,with prevalent stratins of H1N1,H3N2,and type B.Poisson regression model is more acurate in the analysis of influenza-related excess mortalty.