 |
One of the most serious features of influenza is its propensity to cause excess
mortality. In the Asian flu pandemic of 1957, there were 69,800 excess deaths
reported during the winter 1957-58; that is, the number of deaths exceeded that
normally occurred for that period of the year. When H2N2 mutated in 1963, it
caused 43,200 excess deaths. Epidemics of influenza A are invariably accompanied
by excess number of deaths, mostly among those 65 years and older (as
illustrated in next slide). In the history of influenza pandemics, the only
exception was the 1918 pandemic, which caused high mortality among young adults
as well as the elderly. |
