Estimate of excess mortality attributed to influenza in Qingdao, 2001 - 2008

Objective This study established city-level Serfling regression models to estimate the excess mortality attributed to influenza in Qingdao from 2001 - 2002 through 2007 - 2008, and provide the basis for estimating mortality burden attributable to influenza in Chinas northern temperate zone. Methods Age-specific Serfling regression models were established based on the data of underlying respiratory and circulatory (RC) deaths and all cause (AC) deaths to estimate the excess mortality attributed to influenza for three age groups in Qingdao: the all-age, 65-year-old and 65-year-old ones. Results From 2001 - 2002 through 2007 - 2008, the RC-based estimates of the annually averaged excess death attributed to influenza for the all-age, 65-year-old and 65-year-old groups were 1018 (95%CI: 484-1552), 77 (27-127) and 853 (424-1282), respectively; the estimates of the excess mortality for the three groups were 13.8 (95%CI: 6.6-21.1), 1.2 (95%CI: 0.4-1.9) and 108.4 (95%CI: 53.8-162.9) per 100 000 person-years, respectively. Conclusion From 2001 to 2008,the estimated excess deaths attributable to influenza exceeded 1000 each year in Qingdao, of which 90% belonged to the 65-year-old group. Therefore, influenza vaccine inoculation should be extensively provided for the elderly, susceptible population. This study was funded by the China-U.S. Collaborative Program on Emerging Infectious Diseases (No.5U2GGH000018-02)