All-Cause Mortality during First Wave of Pandemic (H1N1) 2009, New South Wales, Australia, 2009

摘要

temperate countries, death rates increase in winter, but in. uenza epidemics often cause greater increases. The death rate time series that occurs without epidemic in. u-enza can be called a seasonal baseline. Differentiating ob-served death rates from the seasonally oscillating baseline provides estimated in. uenza-associated death rates. Dur-ing 2003–2009 in New South Wales, Australia, we used a Ser. ing approach with robust regression to estimate age-specifi c weekly baseline all-cause death rates. Total differ-ences between weekly observed and baseline rates during May–September provided annual estimates of in. uenza-associated death rates. In 2009, which included our fi rst wave of pandemic (H1N1) 2009, the all-age death rate was 6.0 (95% confi dence interval 3.1–8.9) per 100,000 persons lower than baseline. In persons >80 years of age, it was 131.6 (95% confi dence interval 126.2–137.1) per 100,000 lower. This estimate is consistent with a pandemic virus causing mild illness in most persons infected and sparing older persons