Residents line up to have their swab samples collected for nucleic acid testing of possible COVID-19 infection at a testing site in the Xin'gang residential compound in Bayuquan District, Yingkou City, northeast China's Liaoning Province, on May 21, 2021. (Xinhua/Pan Yulong)
Residents line up to have their swab samples collected for nucleic acid testing of possible COVID-19 infection at a testing site in the Xinxing community in Bayuquan District, Yingkou City, northeast China's Liaoning Province, on May 21, 2021. (Xinhua/Pan Yulong)
A medical worker collects a swab sample for nucleic acid testing of possible COVID-19 infection from a resident at a testing site in the Xin'gang residential compound in Bayuquan District, Yingkou City, northeast China's Liaoning Province, on May 21, 2021. (Xinhua/Pan Yulong)
A medical worker collects a swab sample for nucleic acid testing of possible COVID-19 infection from a resident at a testing site in the Xin'gang residential compound in Bayuquan District, Yingkou City, northeast China's Liaoning Province, on May 21, 2021. (Xinhua/Pan Yulong)
Medical workers perform nucleic acid testing of possible COVID-19 infection at a testing site in the Xinxing community in Bayuquan District, Yingkou City, northeast China's Liaoning Province, on May 21, 2021. (Xinhua/Pan Yulong)
A medical worker collects a swab sample for nucleic acid testing of possible COVID-19 infection from a resident at a testing site in the Xinxing community in Bayuquan District, Yingkou City, northeast China's Liaoning Province, on May 21, 2021. (Xinhua/Pan Yulong)
