HOW ARE FLU DEATHS COUNTED?
Flu deaths are difficult to count as deaths are recorded as resulting from pneumonia or a secondary condition. This means authorities have to base their flu mortality figures on estimates. To arrive at a number you subtract the summer deaths from the more numerous winter deaths and call what’s left over ‘excess mortality’. Although this fatality rate can never exactly match the true number of influenza deaths, it serves as the basis for estimating ‘flu-related excess mortality’. The year 2009 was an exception because that was when swine flu was spreading through Australia. Authorities were obliged to report all deaths. The surprising outcome: only 191 documented swine flu deaths nationwide.