Flu Shot Less Effective for Obese Individuals

Flu season is upon us, but preventative flu shots may be ineffectual for people who are obese, according to a new study.

Flu ShotOverweight and obese individuals may face a higher risk of serious illness if they get the flu, according to a recent report published online in the International Journal of Obesity. What’s more, the flu vaccine is less effective for those who carry excess weight, further increasing their risk of sickness.

Vaccines trigger the development of protective antibodies, which help to stave off illness. In the influenza study, the antibody levels from the flu vaccine decreased fourfold in half of the obese patients 11 months after they were vaccinated compared to one month after vaccination. Among healthy weight study participants, less than 25 percent had the same degree of decrease in flu antibodies during the same period.

“Over time, overweight and obese people are not maintaining their antibody levels to the extent that healthy weight people are,” study author Heather A. Paich, a graduate student at the University of North Carolina at Chapel Hill, told HealthDay. “They also appear to have difficulty fighting the flu infection when it does occur.”

Other studies indicate that obesity has been linked to a lower immune system, and many doctors urge obese patients to get two flu shots per year, one in the early fall and another after the New Year.

“Dosages of certain medications often have to be changed based on weight and, in this case, the flu vaccine dosage or administration may need to be changed,” Dr. Scott Kahan, an obesity expert at Johns Hopkins University in Baltimore, told HealthDay.

He added, “It may also be that we need enhanced prevention or other adjunctive strategies in addition to the vaccine for flu protection among people who are overweight or obese.”

The recent study findings also indicated that CD8+ T-cells, a type of white blood cell that help to prime the body’s immune system, are impaired in heavier people. When CD8+ T-cells don’t work properly, the spread and severity of the infection can be significantly higher, putting the individual at risk of further health complications.