Tendência da mortalidade por causas relacionadas à influenza em idosos no Brasil e evidências de plausibilidade de impacto da vacinação, 1992-2005

OBJECTIVE:to describe trends in mortality from influenza-related respiratory diseases in the elderly comparing the periods before and after the annual influenza vaccination campaigns.METHODS:a time-series ecological study using data from the Mortality Information System on deaths among the elderly between 1992 and 2005 where the underlying cause was: pneumonia, influenza, bronchitis and chronic airway obstruction. Analysis performed by linear regression adjusting the historical trend and seasonality.RESULTS:we identified a statistically significant reduction of specific mortality rates in the period after vaccination campaign implementation among the elderly in Brazil as a whole and in the country's Southern, Southeastern and Midwestern regions, and in all age subgroups studied in Brazil and its Southeastern region.CONCLUSION:the results show evidence of the plausibility of a possible protective effect of influenza vaccination campaigns in reducing elderly mortality from respiratory diseases.