Even as officials in Texas and Mississippi lifted statewide mask mandates, researchers from the Centers for Disease Control and Prevention provided new evidence on the importance of face covering, reporting that mask mandates were associated with fewer infections with the coronavirus and Covid. 19 deaths in counties in the United States.
Federal researchers also found that districts that opened restaurants for on-site meals – indoors or outdoors – saw an increase in daily infections about six weeks later and an increase in death rates from Covid-19 about two months later.
The study doesn’t establish cause and effect, but the results agree with other research showing that masks prevent infection and that indoor spaces encourage the spread of the virus through aerosols, tiny particles of breath that linger in the air.
“You have fewer cases and deaths when you wear masks, and you have more cases and deaths when you dine in person,” said Dr. Rochelle P. Walensky, director of the CDC, on Friday. “And so we would advocate for policy, certainly while we are on this plateau of high numbers of cases hearing this public health science.”
The findings come from city and state officials nationwide grappling with growing pressure to reopen schools and businesses amid falling rates of new cases and deaths. Officials recently allowed limited indoor dining in New York City. On Thursday, the Connecticut governor said the state would end capacity restrictions on restaurants, gyms and offices later this month. Masks are still required in both regions.
“The study isn’t surprising,” said Joseph Allen, associate professor at Harvard’s TH Chan School of Public Health and director of the university’s healthy buildings program. “What is surprising is that we see some states ignoring all evidence and are quick to open up, removing mask mandates and opening up full meals.”
Other researchers said the new study confirms the idea that transmission of viruses is often through the air, that physical distancing may not be enough in some situations to stop the spread, and that masks at least partially block airborne particles.
President Biden’s health advisors have said over the past few days that this is not the time to relax. According to a New York Times database, the seven-day average of new cases on Thursday was 62,924 per day.
While that number is down 14 percent from two weeks earlier, new cases remain near the peaks reported last summer. Although the death toll has declined in part due to vaccination campaigns in nursing homes, it remains routine for 2,000 deaths to be reported in a single day.
Mr Biden on Wednesday criticized the decisions of Texas and Mississippi governors to lift statewide mask mandates and reopen businesses without restrictions, calling the plans “a major mistake” reflecting “Neanderthal thinking”.
The president, who asked Americans to wear masks during his first 100 days in office, said it was vital for officials to follow directions from doctors and public health executives as the coronavirus vaccination campaign picks up . By Thursday, around 54 million people had received at least one dose of a Covid-19 vaccine.
“With all this progress, it may seem tempting to try and get back to normal as if the virus was in the rearview mirror,” Andy Slavitt, White House advisor on the pandemic, said Friday. “It is not.”
CDC researchers examined the links between mask mandates, indoor or outdoor restaurants, and coronavirus infections and deaths in the past year between March 1 and December 31. The agency relied on county-level data from state government websites and measured the daily percentage change in coronavirus cases and deaths.
March 5, 2021, 2:50 p.m. ET
Infections and deaths declined after counties mandated the use of masks, the agency found. Daily infections rose about six weeks after the counties allowed restaurants to dine on the premises, and death rates followed two months later.
The report’s authors concluded that mask mandates were associated with a statistically significant decrease in coronavirus cases and death rates within 20 days of implementation. Eating in indoor or outdoor restaurants was linked to rising fall and death rates 41 to 80 days after reopening.
“Government mask mandates and the ban on dining in on-site restaurants help limit potential exposure to SARS-CoV-2 and reduce community transmission of Covid-19,” the authors wrote.
Shortly after the report was released, the CDC amended it, urging facilities resuming serving guests to follow authorities’ guidelines on reducing broadcast in restaurants.
“The message is that it is important to follow CDC guidelines if restaurants are to be opened for on-site dining,” said Gery P. Guy, researcher on the CDC’s Covid Response Team and co-author of the study.
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This includes “everything from employees who stay at home if they show signs of Covid or have tested positive or have been in contact with someone who has Covid, and masks for both employees and customers who are not actively eating or drink, are required, “Dr. Guy said.
Other steps include adequate ventilation, outdoor dining, a two-meter distance from customers, frequent hand washing and disinfection of surfaces that are touched frequently, such as cash registers or payment terminals, door handles and tables.
Even when restaurants limit capacity, an aerosol virus can build up if there is insufficient ventilation, said Dr. All.
“It doesn’t really matter if it’s a restaurant, spin class, gym or choir practice. If you’re inside with no masks, little or no ventilation, we know it’s a higher risk,” he said. “Aerosols for the airways are formed indoors. It’s that simple. This is a real problem for restaurants. “
Linsey Marr, an aerosol delivery expert at Virginia Tech, said Americans couldn’t be expected to follow the latest science and so many simply rely on what is open or closed as an indicator of what for sure is.
But indoor dining is especially risky, she added. People typically sit in a restaurant for an hour or more and don’t wear masks while eating, which makes them susceptible to viruses in the air.
“Limiting capacity will help reduce the risk of transmission, but eating indoors is still a high-risk activity until more people are vaccinated,” she said.
Restaurant workers are particularly exposed. While they can wear masks, guests don’t, reducing protection from the virus. And workers spend many hours indoors on each shift, said Dr. All.
He recommended that restaurant staff wear a double mask, wear a surgical mask covered with a cloth mask, or buy highly efficient masks like N95, which are usually reserved for healthcare workers, or KN95 or KF94 masks to make sure that they are not fake.
“This is not the time to let go of our watch and take back controls when we are so close that many people are being vaccinated,” said Dr. All.
Eileen Sullivan contributed to the coverage.