title: All-cause mortality during first wave of pandemic (H1N1) 2009, New South Wales, Australia, 2009.
abstract: In temperate countries, death rates increase in winter, but influenza epidemics often cause greater increases. The death rate time series that occurs without epidemic influenza can be called a seasonal baseline. Differentiating observed death rates from the seasonally oscillating baseline provides estimated influenza-associated death rates. During 2003-2009 in New South Wales, Australia, we used a Serfling approach with robust regression to estimate age-specific weekly baseline all-cause death rates. Total differences between weekly observed and baseline rates during May-September provided annual estimates of influenza-associated death rates. In 2009, which included our first wave of pandemic (H1N1) 2009, the all-age death rate was 6.0 (95% confidence interval 3.1-8.9) per 100,000 persons lower than baseline. In persons ?80 years of age, it was 131.6 (95% confidence 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.
authors.affiliation: New South Wales Department of Health, North Sydney, New South Wales, Australia. dmusc@doh.health.nsw.gov.au
authors.forename: David J
authors.initials: DJ
authors.lastname: Muscatello
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Cretikos
authors.forename: C Raina
authors.initials: CR
authors.lastname: Macintyre
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D058873:Pandemics; D012621:Seasons; D055815:Young Adult