Wednesday, March 03, 2021

Are mRNA Vaccines Riskier For Obese People?

verywellhealth  |  “Adipose fat is considered like an endocrine organ now, and the immune response in central obesity is that the fat that sits around the organ and abdomen has a much higher prevalence of low immunity in fighting infection and generating antibodies to vaccines,” Desai says.

A 2012 review in the Proceedings Of The Nutrition Society reported that a potential mechanism could be that excess fat hinders access to the nutrients that immune cells need to carry out their daily activities.6

How Vaccination Is Affected

Research has shown that obesity’s role in an impaired immune system often shows itself as lowered vaccine effectiveness. A 2017 study in the journal Annals of the American Thoracic Society found that adults with obesity who were vaccinated with the flu shot were two times more likely to get sick than vaccinated adults who were not obese—despite having the same level of vaccine-induced antibodies.7 The researchers theorized that the effect might be related to impaired T cell function.8

“The data we have so far is from influenza, hepatitis B, and tetanus that shows people who are obese have a decreased immune response to those vaccines,” Desai says.

The Bottom Line

In terms of the new COVID-19 vaccines, Glatt says that there’s no evidence that the mRNA vaccines produced by Moderna and Pfizer would not work in a person who is obese. Rather, Glatt thinks that there are not enough studies to show how well the vaccine works in people who are overweight or obese.

The data that has been released by the U.S. Food and Drug Administration (FDA) and Pfizer show that the clinical trial was representative of people at different body weights—34.8% of vaccinated participants and 35.3% of participants in the placebo group were obese.9

“I think the evidence strongly supports that it is effective in obese patients, but I can’t guarantee that it’s as effective until we get a lot more data,” Glatt says.

Unlike the annual flu shot that uses a weakened or inactive version of the influenza virus, Pfizer and Moderna's COVID-19 vaccines use mRNA technology. Desai says that this changes how the immune response is generated.

However, Desai personally thinks that people who are obese will still respond poorly to the COVID-19 virus because of the body’s inability to handle the infection.

“It’s not how the immune challenge is administered whether through a vaccine or natural disease. The body’s response is weak irrespective of how the challenge is dealt,” Desai says. “People with obesity are most likely going to respond poorly whether it’s the vaccine or the virus. The coronavirus has already proven that it’s not good for obese individuals. In my opinion, no scientific evidence on this yet, [but] the vaccine will work more poorly in obese individuals.”

By that logic, boosting your chances for vaccine effectiveness means controlling for obesity—but Glatt admits that's easier said than done. “It’s a hard thing to accomplish, but it’s an important thing to accomplish.”