IMMUNITY: Why obese people struggle to mount a robust immune response
November 04, 2020 • 1 min read
-- Correlations between Covid-19 and obesity worry health experts
Excess weight goes hand-in-hand with a galaxy of ailments, including high blood pressure and diabetes.
Researchers have also discovered a correlation between Covid-19 and obesity, worrying experts as rates of obesity continue to climb.
People with obesity who caught the coronavirus were more than twice as likely to end up in hospital and nearly 50% more likely to die of Covid-19. Another study showed that among nearly 17,000 hospitalised Covid-19 patients in the US, more than 77% had excess weight or obesity.
Similar links were unmasked during the H1N1 flu pandemic of 2009, when researchers began to notice that infected people with obesity were more likely to wind up in the hospital and to die. Flu vaccines administered in subsequent years performed poorly in individuals with extra weight, who fell ill more often than their peers even after getting their shots.
Part of the problem is mechanical: large amounts of fat can compress the lungs, making it harder to breathe. The blood of people with obesity also seems to be more prone to clotting, plugging up delicate vessels throughout the body and starving tissues of oxygen.
Fat also transmits hormones and other signals that make nearby cells go haywire.
One of fat’s most potent effects appears to involve quelling the body’s initial immune response to the virus, allowing the pathogen to spread unchecked.
When late-arriving immune cells and molecules finally rouse themselves into action, they go berserk, driving uncontrolled bouts of inflammation throughout the body.