A medical worker walks past the nucleic acid test laboratory named Huoyan, or Fire Eye, in Shijiazhuang, north China's Hebei Province, Jan. 26, 2021. As of Jan. 22, a total of 5.28 million nucleic acid samples have been tested in Shijiazhuang's "Huoyan" laboratory since it was put into use from Jan. 8. (Xinhua/Yang Shiyao)