Aerial photo taken on April 4, 2022 shows residents waiting to take nucleic acid tests at a community in Huangpu district of Shanghai, East China. Amid rising numbers of COVID-19 infections in its latest resurgence, Shanghai launched a citywide nucleic acid testing campaign covering the city's more than 24 million residents on April 4. [Photo/Xinhua]
Volunteers help a resident register for nucleic acid test at a community in Songjiang district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
A medical worker from East China's Anhui province takes a swab sample from a resident for nucleic acid test at a community in Huangpu district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
A medical worker from East China's Jiangsu province takes a swab sample from a resident for nucleic acid test at a community in Pudong New Area of East China's Shanghai, April 4, 2022. [Photo/Xinhua]
Medical workers from East China's Zhejiang province prepare to conduct nucleic acid testing for residents at a community in Songjiang district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
A medical worker from East China's Anhui province takes a swab sample from a volunteer for nucleic acid test at a community in Minhang district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
Residents prepare to take nucleic acid tests at a community in Putuo district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
A medical worker takes a swab sample from a man for nucleic acid test in Fengxian district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
Medical workers from East China's Zhejiang province take swab samples from residents for nucleic acid tests at a community in Songjiang district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
Medical workers from East China's Zhejiang province take swab samples from residents for nucleic acid tests at a community in Putuo district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]
A medical worker from East China's Zhejiang province takes a swab sample from a child for nucleic acid test at a community in Songjiang district of Shanghai, East China, April 4, 2022. [Photo/Xinhua]