According to the official, who spoke on the condition of anonymity to discuss the announcement head of time, the CDC is developing a “revised policy framework” for when masks should be required on transit systems based off its newly released “COVID-19 community levels” metric.
As of March 3 more than 90% of the U.S. population is in a location with low or medium COVID-19 Community Levels, where public face-masking is no longer recommended in indoor settings.
“We have to look not only at the science with regard to transmission in masks but also the epidemiology and the frequency that we may encounter a variant of concern or a variant of interest in our travel corridors,” CDC director Dr. Rochelle Walensky said on March 2, explaining why the agency was delaying removing the requirement for transit but allowed people to gather maskless in movie theaters and sports arenas.