22nd June 2009, 12:10 AM
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Cruiser
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Join Date: Apr 2008
Posts: 76
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This should be of considerable comfort to several of our posters.
Quote:
American adults over age 65 account for only 1% of cases of H1N1 flu (swine flu), according to the Centers for Disease Control and Prevention (CDC). The 5- to 24-year-old age group accounts for 64% of all cases, with the remaining 35% falling in the 24-64 range (and not broken down further).
One possibility, said the CDC’s Dr. Anne Schuchat on May 21, is “that older people (over 60) might have been exposed to H1N1 strains a long time ago that might have some relation to the strain we’re seeing now.” That exposure could have come from previous infection or vaccination.
She pointed to laboratory findings published in the CDC’s May 22 Morbidity and Mortality Weekly Report that suggest the elderly, “who are at great risk for seasonal influenza,” have managed to avoid this strain.
During typical seasonal flu epidemics, the elderly frequently have the highest death rates, according to the New England Journal of Medicine; but in pandemics, they are often spared. A pandemic is defined as an epidemic, or sudden outbreak, that spreads over large areas, even worldwide. Pandemics often target the young and healthy, rather than the very young and old. Two health experts believe this is because of the way the body responds to the virus.
What makes younger people more susceptible is that their “vigorous immune systems pour out antibodies to attack the new virus. That can inflame lung cells until they leak fluid, which can overwhelm the lungs,” Dr. Anne Moscona, a flu specialist at Cornell University, told the New York Times in April. Older people, who have had the flu over their lifetimes, “may have some antibodies that provide cross-protection to the new strain,” she said, “and immune responses among the aged are not as vigorous,” which would prevent the same kind of lung problems that the young are experiencing.
“It’s counterintuitive,” Dr. Sanjay Gupta wrote on his blog in April. “Typically, someone with a weakened immune system would be most at risk—the elderly and young—but in this case, it is people with the strongest immune systems. Why? At least in the cases of SARS and avian flu, it was not so much the virus that did the killing, as the body’s response to it—an overwhelming immune response, with inflammation that was deadly to the patients. Think about that. A stronger immune system means a stronger response and a more likely death.”
As the number of cases continues to climb, older adults should not assume that they are immune from the virus. “More seniors might get infected over time as the strain circulates deeper and deeper into our community,” said the CDC’s Dr. Anne Schuchat.
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