Masks Again? Delta Variant’s Spread Prompts Reconsideration of Precautions.

Los Angeles County and the W.H.O. warned that even immunized people should wear masks indoors. Some scientists agreed, but urged a localized approach.

Throughout the pandemic, masks have ranked among the most contentious public health measures in the United States, symbolizing a bitter partisan divide over the role of government and individual liberties. Now, with a new variant of the coronavirus rapidly spreading across the globe, masks are again the focus of conflicting views, and fears, about the course of pandemic and the restrictions required to manage it. The renewed concerns follow the wildfire growth of the Delta variant, a highly infectious form of the virus first detected in India and later identified in at least 85 countries. It now accounts for one in five infections in the United States.