Sun Hewen, a medical worker with Shengjing Hospital of China Medical University, collects nucleic acid samples in Shenyang, capital of northeast China's Liaoning Province, Feb. 16, 2021. Since December last year, some areas in China's northeastern Heilongjiang, Jilin, and Liaoning Provinces reported newly confirmed COVID-19 cases. Related areas responded immediately according to epidemic prevention requirements. Mass nucleic acid testing were conducted in key areas in an effort to stem the spread of the coronavirus. Recently, no new confirmed COVID-19 cases have been reported here for several days. During the Spring Festival vacation, many workers stick to their posts to make sure we can celebrate the festival safely. (Xinhua/Pan Yulong)