As officials in Texas and Mississippi lifted statewide mask mandates, researchers at the Centers for Disease Control and Prevention offered fresh evidence of the importance of mask use in a new study on Friday. Wearing masks, the study reported, was linked to fewer infections with the coronavirus and Covid-19 deaths in counties across the United States.
The researchers also found that counties opening restaurants for on-premises dining — indoors or outdoors — saw a rise in daily infections about six weeks later, and an increase in Covid-19 death rates about two months later.
The study does not prove cause and effect, but the findings square with other research showing that masks prevent infection and that indoor spaces foster the spread of the virus through aerosols, tiny respiratory particles that linger in the air.
“You have decreases in cases and deaths when you wear masks, and you have increases in cases and deaths when you have in-person restaurant dining,” Dr. Rochelle Walensky, the director of the C.D.C., said on Friday. “And so we would advocate for policies, certainly while we’re at this plateau of a high number of cases, that would listen to that public health science.”
The findings come as city and state officials nationwide grapple with growing pressure to reopen schools and businesses amid falling rates of new cases and deaths. Officials recently began allowing limited indoor dining at New York City restaurants. And on Thursday, Connecticut’s governor said the state would end capacity limits on restaurants, gyms and offices later this month. Masks will still be required in both places.
Coronavirus cases and deaths are down significantly across the country compared to the devastating peaks around the holidays. But as more cases of worrisome virus variants have been detected and the U.S. vaccination campaign continues, President Biden and his team have stressed in recent days that now is not the time for Americans to relax, particularly on wearing masks.
The seven-day average of new cases was about 61,000 per day as of Friday, the lowest average since October, according to a New York Times database. But that number was still close to last summer’s highest peak.
Fatalities are falling, too, in part because of vaccinations at nursing homes. Yet the nation is still routinely reporting 2,000 deaths in a single day.
Mr. Biden on Wednesday criticized the decisions by the governors of Texas and Mississippi to lift statewide mask mandates and reopen businesses without restrictions, calling the plans “a big mistake” that reflected “Neanderthal…