Bird flu like 1918 Spanish flu epidemic tends to kill younger people, says WHO

RAW STORY
Published: Saturday July 1, 2006

"Avian flu tends to kill younger people, much as the 1918 Spanish flu epidemic did, the World Health Organization said Friday as it released an analysis of more than 200 cases," begins a story set for the Sunday edition of the New York Times.

"Deaths from the disease surged in the winter for the last three years, the report said, so another upswing in fatal cases can be expected late this year even if the virus does not mutate into a form more easily transmitted," writes Donald G. McNeil Jr.

"Moreover, the report warned, the risk of the virus becoming more transmissible remains high 'because of the widespread distribution of the H5N1 virus in poultry and the continued exposure of humans,'" the Times story continues.

"The median age of confirmed cases of the H5N1 avian flu strain was 20 years, the WHO said in a report published today in the Weekly Epidemiological Record," Bloomberg News reports. "The death rate among patients aged 10 to 19 years was 73 percent, the highest of any age group, it said. Overall, the fatality rate was 56 percent."

World Health Organization report excerpts:

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• The number of new countries reporting human cases increased from 4 to 9 after October 2005, following the geographical extension of outbreaks among avian populations.

• Half of the cases occurred in people under the age of 20 years; 90% of cases occurred in people under the age of 40 years.

• The overall case-fatality rate was 56%. Case fatality was high in all age groups but was highest in persons aged 10 to 39 years.

• The case-fatality profile by age group differs from that seen in seasonal influenza, where mortality is highest in the elderly.

• The overall case-fatality rate was highest in 2004 (73%), followed by 63% to date in 2006, and 43% in 2005.

• Assessment of mortality rates and the time intervals between symptom onset and hospitalization and between symptom onset and death suggests that the illness pattern has not changed substantially during the three years.

• Cases have occurred all year round. However, the incidence of human cases peaked, in each of the three years in which cases have occurred, during the period roughly corresponding to winter and spring in the northern hemisphere. If this pattern continues, an upsurge in cases could be anticipated starting in late 2006 or early 2007.

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Excerpts from NYT article:

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A high death rate among young adults echoes the pattern found in the 1918-1919 epidemic, said Dr. Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. Scientists contend that year's H1N1 virus was also an avian flu that mutated until it spread easily among humans; although it was fatal to only about 2 percent of those who caught it, that was enough to kill between 40 million and 100 million people worldwide.

When the second wave of the Spanish flu struck Boston in the fall of 1918, Osterholm said, the flu death rate among people ages 18 to 30, which had been about 30 per 100,000 people in previous years, soared to 5,700 per 100,000.

The annual flu, by contrast, tends to kill the very young and the very old, often from secondary bacterial pneumonia.

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