Philadelphia became the first major U.S. city to reinstate its indoor mask mandate on Monday after reporting a sharp increase in coronavirus infections, with the city's top health official saying she wanted to forestall a potential new wave driven by an Omicron subvariant.
Confirmed COVID-19 cases have risen more than 50% in 10 days, the threshold at which the city’s guidelines call for people to wear masks indoors, said Dr. Cheryl Bettigole, the health commissioner. Health officials believe the recent spike is being driven by the highly transmissible BA.2 subvariant of Omicron, which has spread rapidly throughout Europe and Asia, and has become dominant in the U.S. in recent weeks.
Health inspectors will begin enforcing the mask mandate at city businesses April 18.
Most states and cities dropped their masking requirements in February and early March following new guidelines from the U.S. Centers for Disease Control and Prevention that put less focus on case counts and more on hospital capacity. The CDC said at that time that with the virus in retreat, most Americans could safely take off their masks.
Philadelphia ended its indoor mask mandate March 2, and Bettigole acknowledged “it was wonderful to feel that sense of normalcy again.”
Confirmed cases have since risen to more than 140 per day — still a fraction of what Philadelphia saw at the height of the Omicron surge — while only 46 patients are in the hospital with COVID-19. The CDC says community spread in Philadelphia remains low, a level at which the agency says that masking can be optional.
Additional reporting by The Associated Press.