NEW YORK (AP) – A new national study adds strong evidence that mask mandates can slow the spread of the coronavirus, and that allowing restaurant dining could lead to more cases and deaths.
The Centers for Disease Control and Prevention released the study Friday.
“All of this is very consistent,” said CDC director Dr. Rochelle Walensky at a White House briefing on Friday. “You have a decrease in cases and deaths when you wear masks, and you have an increase in cases and deaths when you dine at a private restaurant.”
The study was released as some states are repealing 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 COVID-19 restrictions, despite pleas from health officials.
“It’s a solid piece of work that makes it clear that personalized dining is one of the most important things to address if you want to manage the pandemic,” said William Hanage, a Harvard University expert on disease dynamics who is not on the study. was involved.
The new study builds on smaller CDC studies, including one that found that people in 10 states who became infected in July were more likely to have eaten at a restaurant, and another that found mask mandates in 10 states was associated with reduction of hospital admissions.
The CDC researchers looked at US counties placed under state-issued mask mandates and counties that allowed dining at restaurants – both inside and outside at tables. The study looked at data from March through December last year.
The scientists found that mask mandates were linked to decreased 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. That may sound small, but the sheer number of people involved means the impact is growing over time, experts say.
What happens in a restaurant does not stay in a restaurant.
–William Hanage, a Harvard University expert on disease dynamics
“Any day that growth rate declines, the cumulative effect – in terms of cases and deaths – is quite substantial,” said Gery Guy Jr., a CDC scientist who was the lead author of the study.
The reopening of restaurant dining was not followed by a significant increase in the number of cases and deaths in the first 40 days after the restrictions were lifted. But thereafter 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 may be because restaurants did not reopen immediately and because many customers may have been hesitant to dine after restrictions were lifted, Guy said.
There is also always a delay between when people are infected and when they become ill, and longer until when they end up in hospital and die. In the case of eating out, a delay in deaths could also be caused by the fact that the diners themselves may not die, but they could become infected and then spread it to others who get sick and die, Hanage said.
“What happens in a restaurant doesn’t stay in a restaurant,” he said.
CDC officials did not say on-site dining should stop. But they said that when restaurants open, they should take as many preventative measures as possible, such as promoting outdoor dining, having adequate ventilation, masking employees, and urging customers to wear masks when not eating or drinking.
The study had limitations. For example, the researchers tried to make calculations that took into account other policies, such as banning mass gatherings or closing bars, that could affect the number of cases and death rates. But the authors acknowledged they couldn’t explain all possible influences – such as school reopenings.
“It’s always very, very difficult to thoroughly establish causal relationships,” said Hanage. But when you take this along with everything else we know about the virus, it supports the message “of the value of wearing a mask and the danger of dining in a restaurant,” he added.
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