A new study conducted in the United States adds solid evidence that official regulations for wearing masks can help reduce coronavirus infections, and that allowing eating in restaurants can increase cases and deaths.
The Centers for Disease Control and Prevention (CDC) released the study on Friday.
“This is all very coherent,” said Dr. Rochelle Walensky, director of the CDC, during a meeting with reporters at the White House on Friday. increase in cases and deaths when you have people who eat in restaurants. “
The study was released just as some states are canceling official provisions for wearing masks and limits on services provided by restaurants. This week, Texas became the largest state to suspend its order to wear face masks, a trend embraced by many governors despite pleas from health authorities.
“It’s a well-founded piece of work that makes quite convincing arguments that diner presence in restaurants is one of the most important things that needs to be managed if the pandemic is to be controlled,” said William Hanage, an expert at the University. from Harvard in Disease Dynamics who was not involved in the study.
The new research builds on smaller CDC studies, including one that found people who were infected in July from 10 states were more likely to have dined at a restaurant, and another that found that official regulations for wearing face masks in 10 states were linked to reductions in hospitalizations.
CDC investigators examined US counties with official state and county-issued mask-wearing regulations that allowed eating in restaurants, both indoors and outdoors. The study reviewed information from March to December of last year.
The scientists found that there was a relationship between orders to wear masks and a reduction in coronavirus infections, and that improvements in the numbers of new cases and deaths increased over time.
The reductions in growth rates ranged from half a percentage point to almost 2 percentage points. That might sound small, but the sheer number of people involved means the impact grows over time, experts say.
“Every day that the growth rate is going down, the cumulative effect – in terms of cases and deaths – adds up until it’s quite substantial,” said Gery Guy Jr., a CDC scientist and lead author of the study.
The reopening of normal restaurant operations 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 – after that – 2 to 3 percentage points in the rate of increase of deaths.
The delay could be because the restaurants did not reopen immediately and many customers may have been wary of going to dinner right after the restrictions were lifted, Guy said.
Also, there is always a lag between when people get infected and when they get sick, which is even longer when they end up in the hospital and die. In the case of dining out, the delay in deaths could also be due to the fact that the diners themselves might not die, but could become infected and then infect others who become ill and die, Hanage said.
“What happens in a restaurant does not stay in a restaurant,” he said.
CDC officials did not explicitly say that face-to-face service should be suspended at restaurants. But they did say that if restaurants do open, they should take as many preventive measures as possible, such as promoting outdoor tables, having adequate ventilation indoors, employees wearing masks, and asking customers to wear them whenever they are away. eating or drinking.
The study had limitations. For example, the researchers tried to make calculations that took into account other policies, such as bans on mass gatherings or bar closings, that could influence case and death rates. But the authors recognized that they could not take into account all possible influences.
“It’s always very, very difficult to meticulously establish causal relationships,” Hanage said. “But when you take this from everything else we know about the virus, it supports the message” of the value of wearing masks and the danger from dining out to restaurants, he added.