People wait in line to receive test at a nucleic acid testing site in Peking University Hospital, Beijing, capital of China, June 24, 2020. Peking University Hospital has strengthened management of the nucleic acid testing site to avoid risk from the crowd gathering. (Xinhua/Ren Chao)

People register personal information before nucleic acid testing at a nucleic acid testing site in Peking University Hospital, Beijing, capital of China, June 24, 2020. Peking University Hospital has strengthened management of the nucleic acid testing site to avoid risk from the crowd gathering. (Xinhua/Ren Chao)

Guide on swab collection is seen at a nucleic acid testing site in Peking University Hospital, Beijing, capital of China, June 24, 2020. Peking University Hospital has strengthened management of the nucleic acid testing site to avoid risk from the crowd gathering. (Xinhua/Ren Chao)

A medical worker disinfects a colleague's hands at a nucleic acid testing site in Peking University Hospital, Beijing, capital of China, June 24, 2020. Peking University Hospital has strengthened management of the nucleic acid testing site to avoid risk from the crowd gathering. (Xinhua/Ren Chao)

A medical worker (R) collects a throat swab from a woman at a nucleic acid testing site in Peking University Hospital, Beijing, capital of China, June 24, 2020. Peking University Hospital has strengthened management of the nucleic acid testing site to avoid risk from the crowd gathering. (Xinhua/Ren Chao)