The COVID-19 pandemic may be over but a familiar and controversial pandemic-era mandate is making a return in some states. Mask mandates are back at some hospitals in the United States.

Hospitals in a handful of states are requiring staff to wear masks following a rise in the JN-1 variant, the most prevalent form of COVID-19 this winter.

Hospitals in California, Illinois, Massachusetts, New York and Washington D.C. have all brought back mask requirements for selected people in medical settings, according to Newsweek.

Some medical facilities are revisiting mask mandates after the Centers for Disease Control and Prevention (CDC) reported a 10.4% increase in COVID-19 hospitalizations in the week leading up to Dec. 16. CDC data also shows a 3.4% increase in deaths from the virus.