Older Americans Have Some Immunity to Swine Flu, but It’s Not Absolute

When they do contract a severe case of flu, they face greater risk

By: Katharine Greider | Source: AARP Bulletin Today | November 11, 2009

One of the most surprising characteristics of the pandemic H1N1 flu virus galloping across the country this fall is the way it tends to spare older people, striking hardest among the young. More than half of U.S. patients hospitalized with the so-called swine flu have been under the age of 25. Small studies have found that people over age 60 have some antibodies to the bug.

But, whatever immunity to H1N1 older people may enjoy, it’s definitely not foolproof. A recent report on H1N1 cases in California injects a note of caution about the risk profile of people age 50-plus. While they were less likely to get a severe case of H1N1 flu, those who did were more likely than younger people to lose that battle and die.

Published Nov. 4 in the Journal of the American Medical Association, the study examined the first 1,088 H1N1 cases in California that required hospitalization or resulted in death, the bulk of them occurring between last spring and early summer. The median age of these sick patients was only 27, with about a third under 18. While those 50 and older were underrepresented in the group, their fatality rate was 18 to 20 percent, compared with only 11 percent overall.

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