Everyone should get vaccinated against the flu, but obese people have extra reasons to do so. It has long been known that obese people are at increased risk for more severe symptoms and complications if they get the flu, but a study in the Journal of Infectious Diseases in September 2018 has found that they are also likely to remain sick and infectious longer than non-obese people.
Researchers analyzed data from 1,783 people in Nicaragua over three recent flu seasons; 145 of them became ill with the flu. Obese adults who came down with the flu tended to have more severe cases, as expected. What’s more, obese adults with influenza A and two or more flu symptoms shed the virus 40 percent longer than their non-obese counterparts (5.2 vs. 3.7 days). Obese adults with milder illness (one or no flu symptoms, not including fever) shed the influenza A virus twice as long as their non-obese counterparts (3.2 vs. 1.6 days). Obesity did not increase viral shedding in people who had influenza B, which is less common than A (and does not cause pandemics), or in children ages 5 to 17.
Obesity may worsen the course of flu infections by altering immune function and increasing chronic inflammation, the researchers suggested.
The study was funded by the NIH.
This article first appeared in the UC Berkeley Wellness Letter.