The US Centers for Disease Control and Prevention (CDC) has revised its mask-wearing guidelines related to the coronavirus (COVID-19) pandemic.

During its press conference on Friday (February 25), the CDC announced that it would lift the federal mask requirement on school buses although rules for other parts of travel, like airports and train stations, will remain in effect through at least next month.

Guidance for hospitals and nursing homes remain pegged to the agency’s old community transmission thresholds, the CDC said. 

The agency said their new COVID-19 metrics will “inform” new recommendations, but did not offer details on how specifically the agency’s guidance might change. For now, masks remain required in schools in areas of “high” levels of disease, as well as in airports and trains.

The CDC reports that close to three in 10 Americans should continue wearing masks in indoor public areas, including schools. However, millions of others no longer need to based on new guidance that incorporates federal COVID-19 data from hospitals. 

The changes represent one of the largest shifts in the agency’s COVID-19 guidance in months since the CDC said last year that even vaccinated Americans should wear masks indoors in areas deemed by the agency to be at “substantial” or “high” levels of transmission. The CDC’s new recommendations come as a growing number of places have already moved to lift mask requirements, as cases plummeted in the wake of the Omicron variant wave last month.

New CDC framework

Based on the new framework, the CDC has advised that Americans in parts of the country deemed to have “low” levels of the disease — currently about 29.5 per cent of the population will no longer need to wear masks indoors. However, residents of counties at “medium” risk — around 42.2 per cent of the country’s population have been recommended to continue wearing masks if they are at heightened risk of severe disease, like those who have compromised immune systems.

People in counties at a “high” level — around 28.2 per cent of Americans — should still wear a mask indoors. While the daily pace of new cases has slowed by more than 90 per cent nationwide from the peak of the Omicron wave last month, the vast majority of counties had still been in the red zone of “high” transmission by the agency’s original COVID-19 metrics. 

Those thresholds date back to the first year of the pandemic, before vaccinations, prior infections, and growing supplies of effective treatments for the disease blunted the severity of the threat. The average number of COVID-19 patients in hospitals has fallen more than 60 per cent from the record high set during the Omicron wave last month.

For those who were hospitalized, studies published by the agency suggest patients were less likely to face severe illness with Omicron compared to the Delta variant. Many parts of the country had already moved to ease their mask rules ahead of the CDC’s new guidance, from lifting statewide mandates to rolling back rules in schools, based on similar assessments of the disease’s danger.

CDC director Dr Rochelle Walensky told the press conference, “With widespread population immunity, the overall risk of severe disease is now generally lower. Now, as the virus continues to circulate in our communities, we must focus our metrics beyond just cases in the community and direct our efforts toward protecting people at high risk for severe illness, and preventing COVID-19 from overwhelming our hospitals.”