Netflix will require those who work on set in the U.S. to be vaccinated against COVID-19, Deadline reports. The company has thus become the first major Hollywood studio to mandate immunization from actors and those who work with them, which the studio internally refers to as “Zone A” workers. Sean Penn told producers of the Netflix show Gaslit that he will refuse to return to the set until everyone is vaccinated. The United States, and in particular Los Angeles, which is home to Netflix’s production headquarters, is struggling to contain the more contagious delta variant as vaccination rates sag.