Obesity can increase risk of Covid-19 hospitalizations and deaths, may decrease vaccine efficiency: Scientists
As Covid-19 emerged, experts observed that it was hitting obese people harder. Now, a new study paints a clearer picture, showing that it raises the risk of getting infected and hospitalized, in addition to needing critical care and dying of the coronavirus disease. What is more, obesity will likely make potential vaccines less effective, warn researchers.
Scientists reviewed data from 75 studies, covering close to 400,000 coronavirus patients. Their analysis showed that those with obesity -- with a Body Mass Index greater than 30 -- had a 46% higher risk of testing positive for Covid-19 and were 113% more likely to check into a hospital, compared to their non-obese counterparts. The odds of needing critical care and dying stood at 74% and 48%, respectively.
"The critical issue is that Covid highlights how important it is to have a population at a healthy weight level," Dr Barry Popkin, from the UNC Gillings Global School of Public Health and the lead author of the study, tells MEA WorldWide (MEAWW).
According to experts involved in the study, the link between Covid-19 and obesity has been controversial. "There have been no all-encompassing studies on either the role of obesity or metanalyses that address all phases of the obesity-Covid linkage," Popkin says. "We tried to fill a gap as a one-stop document that also addresses the nutritional impact of Covid and policy considerations."
The Centers for Disease Control and Prevention (CDC) estimates that about 42% of Americans are obese. Obesity is linked to certain diseases such as heart disease, stroke, type 2 diabetes, chronic kidney or liver disease -- all of which appear to make Covid-19 worse.
What is more, obesity could make it harder for individuals to fight off infections -- both viral and bacterial. "I’ve studied the effects of obesity on influenza infection and influenza vaccination for many years," Dr Melinda Beck from UNC, tells MEAWW. It impairs immune function against flu, and it will likely do the same with the new coronavirus as well, she added.
Why vaccines may not work as efficiently for people with obesity?
A previous study suggested that the flu vaccine performs poorly on obese individuals. Despite getting their shots, Dr Beck notes, people with obesity were two times more likely to develop influenza, compared to those with a healthy weight.
The reason: the vaccine triggered an immune response, which was not strong enough to protect the individuals. "In fact, the US CDC finally created a second flu vaccine which is stronger for obese individuals and the elderly," Dr Popkin says.
"When testing a vaccine for Covid-19," Dr Beck says, "An individual's weight status should be considered, as we might hypothesize that the vaccine may not work as effectively in the obese population when compared to healthy weight individuals."
The way forward
According to Dr Popkin, the pandemic has forced people to stay cooped up at home. "We’re also not visiting the grocery store as often, which means the demand for highly processed junk foods and sugary beverages that are less expensive and more shelf-stable has increased,” he says. “These cheap foods are high in sugar, sodium and saturated fat, and they’re laden with highly refined carbohydrates, which all increase the risk of not only excess weight gain but also key noncommunicable diseases.”
He calls for actions to reduce the intake of sugary beverages and junk food [ultra-processed food]. Taxation, front-of-package warning labels, and marketing controls or bans will help, he says, adding that it should not be sold in schools. “Given the significant threat Covid-19 represents to individuals with obesity, healthy food policies can play a supportive — and especially important — role in mitigating Covid-19 mortality and morbidity,” he says.
The study is published in the journal Obesity Reviews.