A health worker collects nucleic acid sample from a resident for COVID-19 test at a community in Jiangning district of Nanjing, capital of East China's Jiangsu province, July 24, 2021. A second round of COVID-19 nucleic acid test was launched on July 24 in Jiangning district of Nanjing. The eastern Chinese city on July 23 reported 12 new locally transmitted COVID-19 cases and four asymptomatic ones, local health authorities said on July 24. [Photo/Xinhua]
A health worker collects nucleic acid sample from a resident for COVID-19 test at a community in Jiangning district of Nanjing, capital of East China's Jiangsu province, July 24, 2021. [Photo/Xinhua]
Residents take part in a COVID-19 nucleic acid test at a community in Jiangning district of Nanjing, capital of East China's Jiangsu province, July 24, 2021. [Photo/Xinhua]
Residents take part in a COVID-19 nucleic acid test at a community in Jiangning district of Nanjing, capital of East China's Jiangsu province, July 24, 2021. [Photo/Xinhua]
A health worker collects nucleic acid sample from a resident for COVID-19 test at a community in Jiangning district of Nanjing, capital of East China's Jiangsu province, July 24, 2021. [Photo/Xinhua]
