A new Centers for Disease Control and Prevention report released Friday found that community requirements that support mask use during the pandemic play a large role in county-level COVID-19 case and death growth rates, particularly when it comes to restaurant dining.
An analysis of mask mandates and restaurant reopenings in all U.S. counties from March to December 2020 found that significant drops in daily coronavirus cases and death growth rates occurred within 20 days of implementing mask use.
That’s because the predominant mode of coronavirus transmission is inhaling respiratory droplets expelled from infected people, the agency said, and studies have found masks help in reducing this kind of viral spread.
Meanwhile, jumps in daily COVID-19 case growth rates were observed starting 40 days after restaurant dining reopened — in which people do not wear masks — while daily death growth rates spiked 60 days after allowing on-site dining.
The report comes days after Texas and Mississippi’s governors announced the lifting of state-wide mask mandates and limits on business capacity, allowing 100% operations. Health officials, including President Joe Biden’s chief medical adviser Dr. Anthony Fauci, have criticized the decisions, citing past withdrawals of public health measures that have led to COVID-19 surges.
“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,” the CDC said. “Such efforts are increasingly important given the emergence of highly transmissible SARS-CoV-2 variants in the United States.”
Between March and December 2020, about 74% of U.S. counties had active state-wide mask mandates. The CDC found that these mandates were associated with a 0.5 percentage point decrease in daily COVID-19 case growth rates within 20 days of implementation. A drop of 1.8 percentage points was observed within 100 days.
Mask mandates were also associated with a 0.7 and 1.9 percentage point decrease in daily COVID-19 death growth rates within 20 days and 100 days, respectively, after implementation, according to the report.
Similar trajectories were found after restaurant dining reopened.
About 98% of U.S. counties allowed restaurants to reopen on-site dining during the study period. Within 40 days of the decisions, no “statistically significant” changes in daily COVID-19 case or death growth rates were observed.
But within 60 days and 100 days after restaurant dining restrictions were lifted, coronavirus case growth rate jumped by 0.9 and 1.1 percentage points, respectively.
Changes in death rates were even sharper.
“Allowing on-premises dining at restaurants was associated with 2.2 and 3.0 percentage point increases in the death growth rate 61-80 and 81-100 days, respectively, after restrictions were lifted,” the CDC said.
However, the agency didn’t “differentiate between indoor and outdoor dining, adequacy of ventilation, and adherence to physical distancing and occupancy requirements,” which could have influenced case and death rate trends. The CDC also said case and death growth rates could have increased because people were engaging in close contact elsewhere that was not accounted for in its models.
Recent moves by local leaders to lift coronavirus public health measures were made based on recent drops in cases and deaths across the nation, but CDC Director Dr. Rochelle Walensky said Wednesday during a White House COVID-19 response briefing that the nation continues “to see troubling signs in the trajectory of the pandemic … with the most recent declines in cases and deaths continuing to show signs of stalling.
”The seven-day average of new coronavirus cases jumped 3.5% from the prior seven days, to about 66,000 cases. The seven-day average of deaths also increased 2.2% from the previous seven days to “slightly more than 2,000 deaths per day,” Walensky said.
“We are at a critical nexus in the pandemic. ... On the one hand, cases in the country are leveling off at rates just on the cusp of potential to resurge. ... And on the other hand, stamina has worn thin, fatigue is winning and the exact measures we have taken to stop the pandemic are now too often being flagrantly ignored,” she added.