Study raises concern that COVID-19 vaccine will be less effective for those with obesity

From the novel coronavirus (COVID-19) risk to recovery, the odds are stacked against those with obesity, and a future vaccine may have limited effectiveness for these patients, according to new research led by the University of North Carolina at Chapel Hill and published in the journal Obesity Reviews.

Researchers examined the available published literature on individuals infected with the virus and found that those with obesity were at a greatly increased risk for hospitalization (113 percent), more likely to be admitted to the intensive care unit (74 percent), and had a higher risk of death (48 percent) from the virus.

For the paper, researchers reviewed immunological and biomedical data to provide a detailed layout of the mechanisms and pathways that link obesity with increased risk of COVID-19 as well as an increased likelihood of developing more severe complications from the virus.

Obesity is already associated with numerous underlying risk factors for COVID-19, including hypertension, heart disease type 2 diabetes, and chronic kidney and liver disease, the researchers said.  

Metabolic changes caused by obesity, such as insulin resistance and inflammation, make it difficult for individuals with obesity to fight some infections, a trend that can be seen in other infectious diseases, such as influenza and hepatitis. During times of infection, uncontrolled serum glucose, which is common in individuals with hyperglycemia, can impair immune cell function.

Previous research has demonstrated that the influenza vaccine is less effective in adults with obesity. The same may be true for a future COVID-19 vaccine, according to Melinda Beck, PhD, study co-author and professor of nutrition at Gillings School of Global Public Health.

“Individuals with obesity are also more likely to experience physical ailments that make fighting this disease harder, such as sleep apnea, which increases pulmonary hypertension, or a body mass index that increases difficulties in a hospital setting with intubation,” said Beck in a statement. “"However, we are not saying that the vaccine will be ineffective in populations with obesity, but rather that obesity should be considered as a modifying factor to be considered for vaccine testing. Even a less protective vaccine will still offer some level of immunity.”

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