Obesity May Impair Flu Vaccine

According to a new study in the International Journal of Obesity, obese patients may not be getting full protection from this winter’s flu shot.

The researchers found that:

Influenza vaccine antibody levels decline significantly in obese people compared to healthy weight individuals.

What’s more, responses of CD8+ T cells (a type of white blood cell that plays a key role in the body’s immune system) are defective in heavier people.

“These results suggest that overweight and obese people would be more likely than healthy weight people to experience flu illness following exposure to the flu virus.”

  • The researchers found that about 50 percent of obese study participants had a four-fold decrease in antibody levels at 12 months compared to one month post vaccination.
  • However, less than 25 percent of healthy weight participants had a four-fold decrease in antibody levels.

Also, when study participants’ blood samples were tested in the lab and exposed to a flu virus 12 months after vaccination, about 75 percent of healthy weight people’s CD8+ T cells still expressed interferon-γ, an infection-fighting protein. However, only about 25 percent of obese patients’ cells responded by producing the protein.

And it gets worse.

Not only are obese individuals more likely to get sick…”these findings also suggest overweight and obese people are more likely to become sicker and have more complications. That’s because influenza-specific CD8+ T cells do not protect against infection, but instead act to limit the disease’s progression and severity of disease.”

As if we needed another reason to drop a few pounds.


Douglas Robb

Doug Robb is a personal trainer, a fitness blogger and author, a competitive athlete, and a student of nutrition and exercise science. He's also the co-founder of the Hive Health Media. Since 2008, Doug has expanded his impact by bringing his real-world experience online via the health & fitness blog – Health Habits.

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