The study also examined allowing dining at restaurants.
A new study from the Centers for Disease Control and Prevention found that mask mandates were linked to a decrease in COVID-19 cases and deaths, while allowing dining at restaurants was linked to an increase in both.
The findings come as some states, including Texas and Mississippi, have recently made moves to lift their mask mandates and other restrictions, like dining capacity.
The CDC report, published Friday, examined the association of state mask mandates and orders allowing restaurants to reopen with COVID-19 cases and deaths.
Researchers found that, from March 1 to Dec. 31, mask mandates were associated with a 0.5 percentage point decrease in daily case growth rates and a 0.7 percentage point decrease in death growth rates within 20 days of implementation.
Meanwhile, allowing restaurants to offer indoor or outdoor dining was associated with an increase in daily case growth rates 40 to 100 days later of up to 1.1 percentage point, and an increase in daily death growth rates 61 to 100 days later of up to 3 percentage points.
“Mask mandates and restricting any on-premises dining at restaurants can help limit community transmission of COVID-19 and reduce case and death growth rates,” researchers wrote. “These findings can inform public policies to reduce community spread of COVID-19.”
A combination of factors, such as masking behavior, in-person gatherings and travel, are likely to contribute to an increase or decrease in cases and deaths. Mask mandates may also not be an exact proxy for mask-wearing.
The study did not make a distinction between indoor or outdoor dining.
The CDC encourages people to continue wearing masks in public and maintain proper social distancing, especially due to the presence in the U.S. of the COVID-19 variant that first emerged in the U.K., known as B.1.1.7.
Despite that guidance, several states this week announced they would lift their mask mandates amid falling COVID-19 cases and the vaccine rollout.
On Tuesday, Texas Gov. Greg Abbott said that the state’s mask order will end and businesses can reopen at full capacity as of March 10.
Later that same day, Mississippi Gov. Tate Reeves said the state’s county mask mandates will end and businesses can operate at full capacity starting Wednesday.
Alabama Gov. Kay Ivey said Thursday that effective April 9, masks will be “a matter of personal responsibility and not a government mandate.”
On Friday, Arizona Gov. Doug Ducey also announced that restaurants, bars and other businesses could immediately operate at 100% capacity, while physical distancing and mask protocols will remain in place.
Officials were quick to criticize states’ decisions to lift mask mandates, particularly in Texas. President Joe Biden called Abbott’s decision “Neanderthal thinking,” and Dr. Anthony Fauci, the nation’s leading infectious disease expert, said it was “quite risky.”
The head of the CDC also weighed in, saying that COVID-19 cases in the country are “leveling off at rates just on the cusp of potential to resurge.”
“All the metrics are moving in the right direction,” he told the station. “The numbers are adequate for people to be able to go back to work, open up and get back to a sense of normalcy, especially for our kids and schools, while at the same time making sure that people do follow the best practices.”