A new national study adds strong evidence that masking mandates could slow the spread of the coronavirus, and that it is possible that cases and deaths could be increased for eating in restaurants.
The Centers for Disease Control and Prevention announced the study Friday.
“All of this is very consistent,” said Dr. Rochelle Walensky, director of the CDC, said during an information session in the White House on Friday. “There’s a decrease in cases and deaths if you wear masks, and you increase in cases and deaths if you personally eat in a restaurant.”
The study was released, just as some states revoked mask mandates and restaurant limits. Earlier this week, Texas became the largest state to lift its mask rule, joining a movement by many governors to ease restrictions on Covid-19 despite pleas from health officials.
“This is a solid job that makes the case very strong that eating people is one of the most important things to deal with if you are going to control the pandemic,” said William Hanage, an expert at Harvard University. disease dynamics not involved in the study.
The new research builds on smaller CDC studies, including one that found that people in ten states who became infected in July were more likely to eat in a restaurant and another who found mask mandates in ten states, was associated with the reduction of hospitalizations.
The CDC researchers looked at U.S. provinces placed by state-issued mask mandates and at provinces allowed into the restaurant – inside and at tables outside. The study looked at data from March to December last year.
The scientists found that mask mandates were associated with reduced coronavirus transmission, and that improvements in new cases and deaths increased over time.
The decline in growth rates ranged from half a percentage point to almost 2 percentage points. It may sound small, but the large number of people involved means that the impact grows over time, experts said.
“Every day when the growth rate goes down, the cumulative effect – in terms of cases and deaths – is quite significant,” says Gery Guy Jr., a CDC scientist who was the lead author of the study.
The reopening of restaurant restaurants was not followed by a significant increase in cases and deaths in the first 40 days after the restrictions were lifted. But after that there were increases of about 1 percentage point in the growth rate of cases and – later – 2 to 3 percentage points in the growth rate of deaths.
The delay could be because restaurants did not reopen immediately and because many customers may be reluctant to go in after the restrictions were lifted, Guy said.
There is also always a delay between when people are infected and when they get sick, and longer than when they end up in the hospital and die. In the case of eating out, a delay in deaths can also be caused by the fact that the meals may not die, but that they can become contaminated and then spread to others who become ill and die, Hanage said.
“What happens in a restaurant does not stay in a restaurant,” he said.
CDC officials no longer said the dining room should stop on the premises. But they said if restaurants do open, they should take as many precautionary measures as possible, such as eating outside, having adequate indoor ventilation, disguising employees and appealing to customers to wear masks when not eating or drinking. .
The study had limitations. The researchers, for example, tried to make calculations that take into account other policies, such as banning mass gatherings or bar closures, which could affect consequences and mortality rates. But the authors admitted that they could not explain all possible influences – such as the reopening of the school.
“It’s always very, very difficult to pin down the causal relationships thoroughly,” Hanage said. “But if you take it along with all the other things we know about the virus, it supports the message ‘of the value of wearing a mask and the danger of restaurant wearers, he added.