A medical worker collects a throat swab from a resident in a nucleic acid testing unit at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker disinfects hands in a nucleic acid testing unit at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker transports swab samples for tests at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker works in a movable nucleic acid testing cabin at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a resident in a nucleic acid testing unit at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a resident in a nucleic acid testing unit at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a resident in a nucleic acid testing unit at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

Medical workers collect throat swabs from residents in nucleic acid testing units and a movable cabin at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a resident in a movable nucleic acid testing cabin at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a resident in a movable nucleic acid testing cabin at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)

A medical worker works in a movable nucleic acid testing cabin at a sampling site of Beijing Anzhen Hospital, Beijing, capital of China, June 24, 2020. The nucleic acid testing units and movable cabins were put into use in Beijing Anzhen Hospital to help collect swab samples for nucleic acid testing more efficiently. (Xinhua/Ren Chao)