Restoring normal population mobility to "Covid-zero regions" like China will cause some two million deaths in a year and the key to controlling the virus is developing vaccines that are better at preventing infection, Chinese researchers said.

China's "zero-Covid" restrictions have come under growing scrutiny in recent weeks as it hosts the Winter Olympics in Beijing while using sweeping restrictions to try to prevent the spread of the more infectious Omicron variant.

Chinese scientists and public health specialists have...