Qingdao in East China's Shandong province set a world record by finishing testing on 10.8 million swab samples in 120 hours in the recent fight against the re-emergence of COVID-19, the city's officials said on Sunday.

After new positive patients were reported on Oct 11, the city's authority immediately launched five days of citywide testing, aiming to cover all city residents.

The virus' resurgence, which happened at the city's pulmonary hospital, included 13 confirmed cases in total up to Thursday.

The results of mass testing by 6 pm on Friday showed no additional positive results beyond those already under quarantine. That also meant "the city only took five days to make it clear that the community has not been exposed," said Luan Xin, the city's deputy mayor, at a press conference held on Sunday.

"Moreover, the city was also able to have confirmed patient zero within five days," Luan added.

The outbreak has been traced back to two dock workers and it was spread through poor disinfection of a CT scanning room shared by patients with the novel coronavirus and other conditions at the hospital, according to previous information released at press conferences.

All 13 COVID-19 patients remaining in the hospital were showing good progress, with the application of Western-style medicine and traditional Chinese medicine combined, officials said.

"One of the patients who previously was in serious condition is also getting better," said Sun Yunbo, director of a medical experts team organized to treat the city's recent novel coronavirus outbreak.

Luan also told the press conference that the city is building a special hospital for infectious disease, which is expected to offer 1,000 beds. It will cover an area of 12 hectares, with its floor space reaching 169,000 square meters.

"The hospital will provide general medical service on a daily basis and can meet an urgent need immediately when an emergent public health accident takes place in Qingdao and its surrounding areas," Luan said.

With an investment of 1.58 billion yuan ($235 million), the hospital is expected to be completed at the end of 2022 and put into operation in 2023, Luan added.