Why To Exercise Today: So Your Flu Shot Works

Might the obese need a stronger flu shot?

This I hadn’t heard: The flu shot appears to be less effective in obese people compared to those at normal weight, and the more obese, the less effective the vaccine, according to new research reported in The New York Times. The smallish study raises questions about whether obese people, like the elderly, may need a stronger flu shot to jump-start a less robust immune system.

Researchers studied 74 people given the combination vaccine against three strains of flu in the 2009-10 season, measuring their antibody response one month after getting the shot and then a year later. A third of the group were of normal weight, a third overweight and a third obese. Most were women.

After one month, overweight people had produced about the same level of antibodies as those of normal weight. But 11 months later, more than half of the obese patients had a fourfold or greater decrease in antibodies, a drop seen in just 25 percent of the normal-weight subjects.

The study, published online last week in The International Journal of Obesity, found that the activity of CD8+ T cells, white blood cells that help fight flu infection, also decreased as body mass index increased.

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