One positive COVID-19 case (Case 1, surnamed Li) was found on January 13 in Tanzhou town, Zhongshan city. On the evening of January 14, Zhongshan held the 83rd press briefing on epidemic prevention and control, announcing that gene sequencing indicated the patient was infected with the Omicron variant.

Zhongshan then started a city-wide nucleic acid testing on January 14. By 21:00 January 15, about 5.122 million samples were collected, 4.829 million of which have reported negative and the remaining results are awaited.

An asymptomatic case was newly found among Li's close contacts.

Case 2: Surnamed Liang, 39-year-old female, lives in Qianjin No.2 Road, Tanzhou's Longtang. She was identified as one of Li's same-workshop close contacts on January 13 and was transferred to the designated hotel for quarantine the same day. Her nucleic acid testing results were negative on January 13 and 14 but was positive on January 15.

At present, Liang has been sent to the designated hospital for quarantine and treatment, her contacts are under investigation, and relevant living and working areas of her are under management and control. Terminal disinfection has been implemented in key places she visited.