Analysis

As millennials mingled in bars and restaurants over the summer, and students returned to college campuses, coronavirus infections surged among young adults.

From June through August, the incidence of Covid-19 was highest among adults aged 20 to 29 years old, according to research published on Wednesday by the Centers for Disease Control and Prevention. Young adults accounted for more than 20 percent of all confirmed cases.

When researchers in China were analyzing hospital data of patients with Covid-19, they noticed an odd trend: Very few of the sick patients regularly wore glasses.

In one hospital in Suizhou, China, 276 patients were admitted over a 47 day period, but only 16 patients — less than 6 percent — had myopia or nearsightedness that required them to wear glasses for more than eight hours a day. By comparison, more than 30 percent of similarly aged people in the region needed glasses for nearsightedness, earlier research had shown.