This is a time-trend ecological study to analyze respiratory disease mortality rates from 1980 to 2004. The periods before and after influenza vaccination campaigns for the elderly were examined. In the two years after the campaigns (2000 and 2001), mortality rates decreased, followed by a recovery to levels similar to 1999. This trend is observed for both genders after 2002, although the magnitude of average mortality rates in men is higher than in women. This increase is more evident in individuals over 75 years. Vaccination coverage grew after 2002, even though there are no age-specific vaccine coverage data, or information about vaccination homogeneity in the community. Some hypotheses to explain the inversion of these trends were raised: circulation of others respiratory viruses (syncytial respiratory virus, parainfluenza, adenovirus), after 2002, premature circulation of influenza A virus in 2004 (week 17), environmental factors (pollution and low temperatures), but they were not analyzed in this paper. Etiologic surveillance of flu-like syndromes in the community, as the systematic incorporation of environment indicators, and more detailed vaccination coverage information by the epidemiological surveillance system are emphasized.
Respiratory Disease; Mortality; Influenza; Vaccination; Time Series
