The Zhongshan Command Center for COVID-19 Control and Prevention reported that the latest confirmed case in Macao traveled to and from Zhuhai many times, which is adjacent to Zhongshan's Tanzhou and other towns and sub-districts. Residents in these places have frequent contact with people in Macao and Zhuhai, hence there is a risk of transmission. To eliminate potential risks as early as possible, Zhongshan carried out large-scale nucleic acid testing in Wuguishan District, Sanxiang Town, Shenwan Town and Tanzhou Town on August 4.