As of Thursday, Shanghai had reported nine severe cases during the current COVID-19 outbreak which has resulted in more than 270,000 infections, the Shanghai Municipal Health Commission said on Thursday.

All severe cases, including eight aged between 70 and 93, are receiving medical treatment at designated hospitals, Wu Qianyu, a primary inspector with the commission, said at a press briefing.

"All the elderly cases have serious underlying medical conditions, including severe immune diseases, advanced stage tumors, severe cardiovascular and cerebrovascular diseases, and important organ failures," she said.

None of them has received the COVID-19 vaccine, according to the health commission.

"In response to the rise in the number of confirmed cases, especially the elderly and severe cases, we've coordinated the city's high-quality medical resources and dispatched more teams to the eight designated hospitals to treat COVID cases," Wu said.

"While treating the novel coronavirus pneumonia, medical teams have also carried out multidisciplinary treatment for their underlying diseases to prevent secondary infection."

Shanghai registered 27,719 locally transmitted infections, including 2,573 confirmed cases, on Wednesday. The daily number of newly reported infections in the city has surpassed 20,000 for six consecutive days.