A medical worker takes a swab sample from a citizen for nucleic acid test at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Sun Fanyue)
A medical worker takes a swab sample from a citizen for nucleic acid test at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Zhao Zishuo)
A medical worker takes a swab sample from a citizen for nucleic acid test at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Zhao Zishuo)
A medical worker takes a swab sample from a child for nucleic acid test at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Sun Fanyue)
Medical workers transport boxes containing swab samples for nucleic acid tests at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Sun Fanyue)
A medical worker helps a kid register for nucleic acid test at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Sun Fanyue)
A medical worker takes a swab sample from a citizen for nucleic acid test at a COVID-19 testing site in north China's Tianjin, Jan. 15, 2022. North China's Tianjin Municipality launched the third round of citywide nucleic acid testing at 7 a.m. Saturday. (Xinhua/Zhao Zishuo)
