Testing continued as Shanghai entered its seventh day of lockdown on Friday with the COVID-19 resurgence that began on March 1 having caused more than 130,000 infections including one severe case.

The city added 824 confirmed cases on Thursday, more than double Wednesday's tally, along with an increasing number of new asymptomatic carriers that pushed the daily total of new infections to another high of 21,222.

"We are now at a critical point in the fight against the virus, with rather high numbers of infections revealed during grid screenings carried out recently and characterized by cluster transmissions in communities," Wu Qianyu, a senior inspector with the municipal health commission, said at a news briefing on Friday.

According to official data, the youngest patient so far is an infant born just last week, whereas the eldest is 98 years old. The majority－69 percent－of the 4,393 confirmed cases so far have been those aged 18 to 60, while 15 percent of the cases are those aged 18 and below.

The latest outbreak has resulted in one severe case, with the patient currently receiving treatment, Wu said.

To curb the outbreak, the city launched another round of citywide testing on Friday amid the ongoing lockdown beginning April 1, including nucleic acid tests and antigen tests for people with different exposure risks, according to the announcement by the municipal government.

To ensure swift quarantine and treatment of the infected, the city has been racing against time to set up new makeshift hospitals and quarantine facilities, said Jin Chen, deputy director of the city's housing and construction commission.

The city has also been improving patient-centered care in makeshift hospitals. According to Fan Jia, president of Zhongshan Hospital Affiliated to Fudan University, over 300 medics and management staff members from the hospital have been assigned to a makeshift hospital converted from an indoor stadium in Minhang district, one of the worst-hit areas in Shanghai with 2,257 locally transmitted infections on Thursday alone.

Most of the participating medics joined the initial battle against the virus in Wuhan, Hubei province, in 2020, Fan said. A team led by academicians of the Chinese Academy of Sciences and composed of experts in the medical industry was also established to work on diagnosis and treatment specifications, offer consultation and assist in treatment at the makeshift hospital.

"The strategy aims to enhance the efficiency of treatment for the safety of patients in order to shorten the average length of stay in hospitals as much as possible. Furthermore, we care for children, women and the elderly. Personalized medical plans are also offered to those with other diseases aside from COVID-19. Standard meals, bedding and internet connections are provided for patients as well," he said.

Moreover, Fan added that the hospital also went the extra mile to ensure effective management of staff members, care for frontline health workers and provide safety guarantees in the facility.