America’s Obesity Epidemic Threatens Effectiveness of Any COVID Vaccine

Fat tissue seems to affect the immune system in multiple ways, including triggering ongoing, low-grade inflammation

Widespread obesity means Americans are more likely to have a severe reaction to COVID-19 and less likely to develop strong immunity through a vaccine. Alfredo Estrella/AFP/Getty Images

In the United States, where at least 4.6 million people have been infected and nearly 155,000 have died, the promise of a vaccine is hampered by a vexing epidemic that long preceded COVID-19: obesity.