Massive COVID-19 nucleic acid test held in Xining（4）

A medical worker collects a swab sample from a resident at a COVID-19 testing site in Chengxi District of Xining, northwest China's Qinghai Province, Nov. 2, 2021. Xining has set up 121 testing sites in Chengxi District for massive COVID-19 nucleic acid testing. (Xinhua/Zhang Manyi)