A new study from the CDC takes a closer look at the *potential* impact of statewide mask mandates and indoor dining on COVID-19 cases.
Here’s what the study shows & why it matters.
- Time period: March 1 – Dec. 31, 2020
- Many states had mandates/restrictions in place early in the pandemic and lifted mitigation efforts at varying times.
- The CDC compared before/after data at a county level.
- Outcomes examined: growth rate of COVID-19 cases by county and county deaths (death growth rates) in the days after implementation (days 1-20, 21-40, 41-60, 61-80, + 81-100).
- Within 20 days of a statewide mask mandate, counties showed a decrease in COVID-19 cases and deaths.
- After 40 days (about 6 wks) after restaurants “reopened,” counties showed an increase in COVID-19 cases & a rise in deaths several weeks later.
- “State mask mandates and prohibiting on-premises dining at restaurants help limit potential exposure to SARS-CoV-2, reducing community transmission of COVID-19.” -CDC
“You have decreases in cases and deaths when you wear masks, and you have increases in cases and deaths when you have in-person restaurant dining.”
CDC Director Dr. Rochelle Walensky said with the level of transmission and COVID-19 variants in 48 states, this study shows the value of mitigation efforts: “It also serves as a warning about prematurely lifting these prevention measures."
Limitations Of The Study
- “Compliance with and enforcement of policies were not measured.” CDC
- Most of America permits indoor dining of *some kind* – the CDC did not measure differences in how it was practiced (Did restaurants follow capacity limits? Outdoor dining available? etc.).
- Varying mitigation efforts place to place (such as gathering restrictions + distancing) could impact results.
“If a positive correlation between ice cream sales and shark attacks is found, that would not mean that ice cream causes shark attacks.”
The National Restaurant Association calls the CDC study “an ill-informed attack on the industry hardest-hit by the pandemic,” arguing restaurants typically have to follow many safety requirements to operate during the pandemic. The group says "myriad variables" could have led to the CDC's conclusions, as in the maxim "Correlation does not equal causation."
“We are maintaining the masks.”
Connecticut Governor Ned Lamont who announced his state will resume restaurant dining at 100% capacity but with some restrictions (such as earlier closing times). Connecticut will maintain the statewide mask mandate, unlike other states such as Texas and Mississippi that will forego the policy. The differences in the timing of state mitigation efforts, infection rates, and cultural & regional differences in lifestyle are all variables to research.
The CDC calls the difference of infections and statewide mask mandates (an ultimate decrease of nearly 2%) & indoor dining reopening (an increase of about 1%) "statistically significant." Those statistics slightly change during every 20-day interval the study highlights. You can see the percentages for yourself on our source page.
(Helpful tip – the PDF file available through this link shows some of the charts more clearly than what’s available on the CDC website)
CDC Director Statement: “You have decreases in cases and deaths when you wear masks, and you have increases in cases and deaths when you have in-person restaurant dining,” Dr. Rochelle P. Walensky, the director of the C.D.C., said on Friday. “And so we would advocate for policies, certainly while we’re at this plateau of a high number of cases, that would listen to that public health science.” (NYT)
“This report is a critical reminder that with the current levels of Covid-19 in communities, and the continued spread of more transmissible virus variants, which have now been detected in 48 states, strictly followed prevention measures remain essential for putting an end to this pandemic,” CDC Director Dr. Rochelle Walensky said at a White House Covid-19 press briefing on Friday.
“It also serves as a warning about prematurely lifting these prevention measures,” Walensky said. (CNBC)
by Jenna Lee,