AGES experts have taken a critical look at influenza-associated excess mortality in a survey. Up to 6,000 fatalities per influenza season were reported in Austria, a number that is significantly higher than in neighbouring countries.

The objective of this analysis was to create a reliable estimate of influenza-associated excess mortality: the influenza-associated excess mortality rates for 2000/2001 up to 2008/2009 were calculated by taking the difference between the entire mortality rate observed during an influenza season and the mortality to be expected in the same period without increased influenza activity. Influenza activity was determined using the influenza activity index, which is based on the data provided by the clinical influenza sentinel system.

The study showed influenza-associated excess mortality reached its peak in the seasons 2002/2003 season (1060 excess fatalities), 2004/2005 (1102 excess fatalities) and 2008/2009 (1192 excess fatalities). The rising trend during the observation period of 10 years goes hand-in-hand with the increased aging of the Austrian population (share of over 65 year-olds: 2001: 15.5 %; 2009: 17.5 %).

The current results provided by AGES correspond with the estimates of influenza-associated excess mortality for Germany and Switzerland. Reliable data with regards to excess fatalities are a requirement for achieving and maintaining high, annual vaccination coverage.

The survey was published in Wiener klinischen Wochenschrift.