New insights into historical influenza pandemics published

A special supplement published by Vaccine reveals new insights about historical influenza pandemics, including how the 1889 pandemic affected different age-groups and the strange age distribution in the pandemic of 1918-1920.
The supplement includes a dozen research reports, six focusing on the 1918 pandemic. The issue is supported by the International Influenza Unit of the Office of Global Affairs at the Department of Health and Human Services and the Fogarty International Center of the National Institutes of Health, CIDRAP News reports.
A team of French researchers used European and United States records to examine the mortality rates during the 1889 pandemic.
"We conclude that the age-specific attack rates of the 1889 pandemic were most similar to those of the 1968 pandemic and that influenza-related mortality rates did not follow a W-shaped curve as was observed during the 1918 pandemic," the report said, according to CIDRAP News. "Adding 1889 to the short catalogue of influenza pandemics previously studied makes the 1918 pandemic even more exceptional in terms of mortality burden and age distribution of deaths."
A study led by a team of Danish and American researchers found that while people between the ages of 15 and 64 were hit hard by pandemics before 1918-1920, people over 65 were less affected, probably due to childhood exposure to a similar virus. This was the case for older people during the 2009 H1N1 pandemic as well.
As age patterns of flu-related deaths returned to pre-pandemic status, the burden shifted to the elderly after 1925.
"The first post-pandemic season associated with high excess mortality rates in individuals over 65 years was 1928-1929, with 73 percent of excess deaths occurring among seniors," the report says, according to CIDRAP News.
Another report examined the burden of illness in Denmark during the 2009 H1N1 pandemic and found that the highest attack rate was in children five to 14 years old and that the present pandemic compares favorably with past pandemics.

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