1951 Influenza Epidemic, England and Wales, Canada, and the United States

摘要

Influenza poses a continuing public health threat inepidemic and pandemic seasons. The 1951 influenza epi-demic (A/H1N1) caused an unusually high death toll inEngland; in particular, weekly deaths in Liverpool even sur-passed those of the 1918 pandemic. We further quantifiedthe death rate of the 1951 epidemic in 3 countries. InEngland and Canada, we found that excess death ratesfrom pneumonia and influenza and all causes were sub-stantially higher for the 1951 epidemic than for the 1957and 1968 pandemics (by >50%). The age-specific patternof deaths in 1951 was consistent with that of other interpan-demic seasons; no age shift to younger age groups, remi-niscent of pandemics, occurred in the death rate. Incontrast to England and Canada, the 1951 epidemic wasnot particularly severe in the United States. Why this epi-demic was so severe in some areas but not others remainsunknown and highlights major gaps in our understanding ofinterpandemic influenza