Four Shanghai hospitals resumed medical service early Saturday after more than 30 hours of closed-loop management for COVID-19 pandemic prevention and control, the Shanghai government announced on Saturday.

The four medical institutions – Ruijin Hospital, Zhongshan Hospital, Tongji Hospital and the Central Hospital of Minhang District – have resumed outpatient and emergency treatment service as usual, and extra outpatient service will be provided on Sunday.

At around 7 am Saturday, the first ambulance after the hospital's closed-loop management concluded arrived at Ruijin, transporting a hemophilia patient suffering from gastrointestinal bleeding.

Shanghai reported three confirmed local COVID-19 cases on Thursday after nearly four months of zero local novel coronavirus infections in the city. No new cases were reported since Thursday.

At around 4 pm Thursday, Ruijin was the first hospital put under closed-loop management. As of the end of Friday, more than 20 hospitals, including Shanghai Cancer Center and the downtown campus of the Children's Hospital of Shanghai, had suspended medical service.

Lu Taohong, vice-director of the Shanghai Municipal Health Commission, told People's Daily on Friday that there was no hospital infection involved.

"In response to confusion from the public about why so many medical institutions had to suspended service, it's because the three confirmed cases have more than 200 close contacts," Lu said. "Some of them had been to hospitals for medical treatment either for themselves or accompanying family members."

"According to national protocol, such hospitals must undergo a '2 plus 12' management," he said, which means the hospitals must be subject to two days of closed-loop management with all individuals inside undergoing nucleic acid test twice, 24 hours apart, and all these people must proceed with 12 days of self-health monitoring.

At least 10 medical institutions, including Renji Hospital and Children's Hospital of Fudan University, announced on Friday that they will provide outpatient service throughout this weekend to provide sufficient medical service options for residents.