We’ve all heard the warnings about overweight and obesity, and how they increase risk for chronic diseases like type 2 diabetes, heart disease and even some forms of cancer. But did you know that being overweight or obese can also affect how well you respond to your annual flu shot?
During the 2009 H1N1 outbreak, researchers noticed that overweight and obese people seemed more likely to get the flu than individuals who had a healthy body mass index (BMI). A study published online by the International Journal of Obesity last fall – when we were all dutifully getting our shots – seems to confirm that excess weight “may impair the ability to mount a protective immune response to influenza virus.” According to the study, levels of flu vaccine antibodies declined quickly in overweight and obese individuals, making it more difficult to get through the flu season without becoming sick.
Researchers also found that white blood cells key to the body’s immune defense (called CD8+ T cells) didn’t respond as they should in overweight and obese people – in other words, these people experienced more severe flu symptoms.
More research needs to be done, but the study gives us one additional reason to try to shed extra pounds. The flu attacks several million people around the world a year, according to the World Health Organization, and causes up to half a million deaths.