BEIJING - China said the worst was over in its battle against Covid-19 ahead of what is expected to be the busiest day of travel in years on Friday, a mass movement of people that has fed fears of a further surge in infections.

Vice-Premier Sun Chunlan, who oversees China’s virus response, said that the outbreak was at a “relatively low” level, state media reported late on Thursday, after health officials said the number of Covid-19 patients in clinics, emergency rooms and with critical conditions had peaked.