[Mortality associated with peak seasons of influenza virus circulation in Bogotá, Colombia, 1997-2005]

To estimate potential excess mortality attributable to influenza viruses A and B and human respiratory syncytial virus (HRSV) during peak seasons of influenza virus circulation in Colombia from 1997 to 2005.A comparison of monthly, general mortality rates from pneumonia in children under 5 years of age and from pneumonia and cardiovascular disease in those more than 60 years of age in Bogota, Colombia, were compared to the city's peak seasons of influenza virus circulation. Mortality data were obtained from the National Bureau of Statistics of Colombia; peak seasons of virus circulation were defined as contiguous months in which the number of isolates was equal to or greater than half the total number of isolates for the year. Incidence rate ratios (IRR) and their 95% confidence intervals (95%CI) were determined.Influenza A demonstrated a pattern of seasonal circulation, but influenza B and HRSV did not. The increased circulation of influenza virus was associated with an average annual increase of 5% in overall mortality during the study period (IRR = 1.05; 95%CI: 1.046-1.064). During seasons of increased circulation of influenza viruses, the combined mortality from pneumonia and influenza for all ages was 11% higher than it was at other times (IRR = 1.11; 95%CI: 1.051-1.178).During peak seasons of influenza virus circulation in Colombia, there can be increased mortality, particularly from pneumonia and cardiovascular disease among those more than 60 years of age. Preventive actions specific to protecting against influenza should be taken, especially in these two age groups.