Photo: Xinhua

A man tested positive again for COVID-19 in Shanghai this week, months after he was discharged from hospital after recovering from the novel coronavirus pneumonia, Shanghai health authorities said on Thursday.

The man, diagnosed as a confirmed imported COVID-19 case in April after returning to China, had received treatment in Northeast China's Jilin Province and later recovered. 

He was then diagnosed as an asymptomatic carrier at a Shanghai hospital on August 10, one day after he entered the city with his wife to see a doctor.

The man is being treated in isolation at a local designated hospital. His 23 close contacts in Shanghai including his wife all tested negative for COVID-19, and are under quarantine for medical observation.

This is the second relapse COVID-19 case reported in the Chinese mainland in the last seven days. On August 9, a 68-year-old woman in Central China's Hubei Province also tested positive for the virus after she recovered and was discharged from hospital in February. 

Relapse COVID-19 patients are not infectious, according to scientific studies, virologist Yang Zhanqiu told the Global Times.