GENEVA–(ENEWSPF)–22 December 2009. Efforts to assess the severity of the H1N1 influenza pandemic sometimes compare numbers of confirmed deaths with those estimated for seasonal influenza, either nationally or worldwide. Such comparisons are not reliable for several reasons and can be misleading.
Numbers of deaths for seasonal influenza are estimates. They use statistical models designed to calculate so-called excess mortality that occurs during the period when influenza viruses are circulating widely in a given population.
