Some factors influencing mortality from influenza.

During the winter of 1969-70 the influenza virus variant A2/Hong Kong/68 caused an outbreak of influenza in Glasgow that was associated with considerable morbidity and mortality. An analysis was made of 135 death certificates in which influenza was mentioned as a principal or contributory cause of death. Over half the deaths occurred in patients aged 65 years or over. Pre-existing disease, especially cardiovascular conditions, played an important role in influenza mortality. None the less, among the poorer classes influenza per se was the principal cause of more than half the total number of deaths. The peak number of deaths occurred during the coldest weather of the season. This study again demonstrated that mortality from all respiratory diseases is a good indication of influenzal activity in a community.