The Centers for Disease Control and Prevention (CDC) on Feb. 25 drastically changed a key measure that is used by officials across the country to determine whether or not to require mask-wearing.
The dramatic switch comes because the CDC switched from only using COVID-19 cases as a factor and are taking into account other metrics, including hospitalizations.
“This updated approach focuses on directing our prevention efforts toward protecting people at high risk for severe ailments and preventing hospitals and healthcare systems from being overwhelmed,” Dr. Rochelle Walensky, the CDC’s director, told reporters on a call.
Walensky said the CDC “came up with these indicators, including new hospital admissions and hospital beds utilized, and complimented them with case incidents to really create a package of metrics to be able to understand what’s happening at the local level.”
The CDC will count all hospitalizations, regardless of whether the patients were admitted because of COVID-19 or tested positive for COVID-19 after being admitted for another reason.
The previous measures for transmission, unchanged since 2020 before Friday, counted a county as having substantial risk of COVID-19 transmission if there were as few as 50 new COVID-19 cases per 100,000 people in the past 7 days, or the percentage of positive tests was at least 8 percent in the same timeframe.
High transmission risk meant a county had 100 or more new cases per 100,000 people or 10 percent or higher positive tests in the past 7 days.
Under the scheme, over 95 percent of the country on Feb. 25 was labeled substantial or high risk, even though COVID-19 cases have plunged in recent weeks and just 77,458 cases were recorded nationwide on Feb. 23.
After the update, the substantial risk column was removed. Now, just 37 percent of U.S. counties are deemed at high risk.
People who live in those counties, representing 28.2 percent of the U.S. population, are advised to wear a mask in public indoor settings such as schools.
In the rest of the counties, people are not advised to wear masks unless they test positive for COVID-19 or have been exposed to somebody with COVID-19.
People can still wear masks if they feel more comfortable, Walensky said.
The CDC had resisted calls to alter its community risk metric for months, even after many of the governors who had kept masking requirements in place announced in early February those requirements would be eased or withdrawn.
Walensky signaled a change might be coming in a recent briefing, acknowledging the sharp drop in cases and hospitalizations. But she’s also indicated that people would be urged to mask up in the future if the CDC thinks it’s necessary.
“We want to give people a break from things like mask-wearing, when these metrics are better, and then have the ability to reach for them again should things worsen,” she said.
Jeffrey Zients, a White House official, did not deny the White House had been in touch with the CDC on revising its masking recommendations but said the CDC was “in the lead here on both the substance and the timing of masking guidance.”
Federal health officials say masks are effective at preventing COVID-19 transmission, pointing primarily to studies the CDC has published in its quasi-journal. One such paper, published Feb. 4, relied on self-reporting and found no statistically significant benefit for wearing cloth masks. Critics say the studies don’t support mask-wearing, especially wearing cloth masks.