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Immunosenescence - Age-associated immune deficiency

"influenza vaccines are only 30-40% effective in preventing clinical illness among the elderly" [1]

While vaccinations remain one of the most potent weapons we have against infectious disease, they don't work as well as our immune systems age. Scientists are conducting experiments to understand why vaccines are less effective in older adults and what can be done to make them more effective.

Influenza takes its heaviest toll among those with weakened immune systems, including the old. Scientists at the Mayo Clinic in Rochester, Minnesota, published the results of studies done on influenza vaccine in older adults in the December 2001 issue of the Journal of Virology. They monitored 153 residents of a retirement community, aged 65 to 98 years, who had received influenza vaccine. The vaccine was trivalent, containing elements of three different flu strains. At 28 days, the scientists found that only 17% of the persons vaccinated were immune to all 3 strains. Forty-six percent were found to have no immunity to any of the three strains. The likelihood of the subjects responding to the vaccine was found to decline with age.

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The aging of the immune system or immunosenescence is believed to contribute to the increased incidence of cancer seen among older adults. As in so many other areas of medicine, mouse models of cancer are instructive as to how and why this might be.

In the August 2001 issue of Cancer, Immunology and Immunotherapy, researchers at the Hines VA Hospital in Illinois published their observations of lung cancer in aging mice. They noted that CD4+ cells, a line of T cells, declined in number as mice aged. They also noted that in mice with lung cancer, those CD4+ cells were far less likely to produce interferon, a natural anti-cancer substance. Another population of T cells known as CD8+ cells were present in their typical numbers in aging mice, but the CD8+ cells were less able to produce interferon.


You think that brushing your teeth, drinking clean water, breathing clean air and eating the right foods are important. You are correct, but what do you do to strengthen your immune system and do you wait too long to do it after immunosenescence takes it tollquestion_mark

[1] Vaccine. 2003 Mar 7; 21 (11-12): 1180-6. ; J Med Virol. 2003 Apr; 69(4): 560-7.; Hum Immunol. 1994 Jul; 40 (3): 202-9.