A medical worker works at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker gives an infusion to patient at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Sun Keyu (R), director of the emergency department, talks with a colleague at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Medical workers treat patients at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker checks records at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker talks to a family member of a patient at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Sun Keyu (1st L), director of the emergency department, talks with colleagues at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker talks to a family member of patient at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Medical workers receive a patient from an ambulance at Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Medical workers prepare medicine at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker inputs treating records at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker gives an infusion to patient at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Sun Keyu (L), director of the emergency department, talks with a colleague at Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker takes a call at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

A medical worker talks with a family member of a patient at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Medical workers are busy working at the emergency room of Minhang Hospital affiliated to Fudan University in Shanghai, east China, April 20, 2022. In order to better undertake the task of treating critically ill patients during the recent COVID-19 outbreak in Shanghai, Minhang Hospital affiliated to Fudan University reorganized its emergency team with 31 doctors and more than 100 nurses.

Sun Keyu, director of the emergency department who has more than 20 years of experience in emergency treatment, leads the team to stick to their posts since March. (Xinhua/Zhang Jiansong)

Chief nurse Jin Yi (L) learns about the condition of a patient in Shanghai Tenth People's Hospital in east China's Shanghai, April 20, 2022. Shanghai Tenth People's Hospital has made efforts to ensure medical services for citizens with epidemic prevention and control measures amid recent resurgence of COVID-19 in the city. (Xinhua/Chen Jianli)

Zou Jun (L), chief physician of ophthalmology department, conducts examination for a patient in Shanghai Tenth People's Hospital in east China's Shanghai, April 20, 2022. Shanghai Tenth People's Hospital has made efforts to ensure medical services for citizens with epidemic prevention and control measures amid recent resurgence of COVID-19 in the city. (Xinhua/Chen Jianli)

Zou Jun (L), chief physician of ophthalmology department, sanitizes a patient's hands after examination in Shanghai Tenth People's Hospital in east China's Shanghai, April 20, 2022. Shanghai Tenth People's Hospital has made efforts to ensure medical services for citizens with epidemic prevention and control measures amid recent resurgence of COVID-19 in the city. (Xinhua/Chen Jianli)

A nurse makes preparations in Shanghai Tenth People's Hospital in east China's Shanghai, April 20, 2022. Shanghai Tenth People's Hospital has made efforts to ensure medical services for citizens with epidemic prevention and control measures amid recent resurgence of COVID-19 in the city. (Xinhua/Chen Jianli)