China's Hebei Province is arranging for plasma donated by recovered COVID-19 patients in Wuhan to be sent to help treat local patients in serious condition, local authorities said at a press briefing on Saturday afternoon. The blood plasma, taken from patients who have recovered from COVID-19, usually contains antibodies that may help severe patients battle the disease. 

As of Saturday, the province has reported 139 new coronavirus cases, among whom seven are critically ill. These seven cases are mostly senior patients with underlying diseases, such as hypertension, cardiovascular diseases, and diabetes, said Duan Yunbo, deputy director of the provincial health commission of Hebei.

The plasma to be transferred from Wuhan to treat the patients in Hebei may not be new because there has been a limited number of COVID-19 patients in China since the epidemic was largely put under control around May, Dr. Li Tianbao from the University of Texas Health Science Center at San Antonio told CGTN. 

He explained that the antibodies can be maintained for half a year if the blood was stored at the right temperature.  

Multiple studies have been conducted on the effectiveness of the treatment. The most recent one, published in the medical journal The New England Journal of Medicine on January 6, concluded that an early dose of blood plasma from recovered patients helps prevent the progression of the disease to a more severe stage, and the antibodies in it are responsible for the therapeutic effect. 

During the COVID-19 outbreak in Wuhan last winter, convalescent plasma was used to treat severe patients in Jinyintan hospital, showing positive effects. Since then, Chinese health authorities have encouraged people who recovered from COVID-19 to donate their blood plasma to help more patients.

The therapy has also been adopted in other countries, including the United States and Brazil.