Medical workers work at the Huo-yan (Fire Eye) nucleic acid test laboratory at Asian Games City Comprehensive Gymnasium in Panyu District, Guangzhou City, Guangdong Province, June 7, 2021. (Photo: China News Service)

Medical workers work at the Huo-yan laboratory at Asian Games City Comprehensive Gymnasium in Panyu District, Guangzhou City, Guangdong Province, June 7, 2021. (Photo: China News Service)

Medical workers who will enter the Huo-Yan laboratory wear protective suit, Panyu District, Guangzhou City, Guangdong Province, June 7, 2021. (Photo: China News Service)

Medical workers write their name on protective suit before entering the Huo-yan laboratory in Panyu District, Guangzhou City, Guangdong Province, June 7, 2021. (Photo: China News Service)

Medical workers work at the Huo-yan laboratory at Asian Games City Comprehensive Gymnasium in Panyu District, Guangzhou City, Guangdong Province, June 7, 2021. (Photo: China News Service)

Medical workers enter the Huo-Yan laboratory at Asian Games City Comprehensive Gymnasium in Panyu District, Guangzhou City, Guangdong Province, June 7, 2021. (Photo: China News Service)