BEIJING, Feb. 14 (Xinhua) -- China has developed convalescent plasma to treat patients who are infected with the novel coronavirus (COVID-19), according to the China National Biotec Group.

The company said they have collected plasma from some recovered patients to prepare therapeutic products including convalescent plasma and immune globulin.

After strict blood biosafety tests, virus inactivation and antiviral activity tests, they have successfully developed convalescent plasma for clinical treatment and have used it to treat critically ill patients.

The company has set up a team to use special equipment to collect plasma from recovered patients in Wuhan since Jan. 20.

Three critically ill patients in a hospital in the Jiangxia District of Wuhan received convalescent plasma treatment on Feb. 8. Currently, more than 10 critically ill patients have received the treatment, the company said.

According to clinical results, 12 to 24 hours after the patients received the treatment, they have shown improved clinical symptoms, with main inflammatory indexes decreased significantly and some key indexes such as blood oxygen saturation improving comprehensively.

Experts said that based on the clinical pathological process, most of the cured patients will produce specific antibodies against the virus in their bodies, which can help kill the virus.

The convalescent plasma-derived therapeutic product is made from the plasma donated by cured patients after virus inactivation and detection of multiple pathogenic microorganisms.

Convalescent plasma therapy may be an effective way to reduce the mortality rate of critically ill patients, according to experts.

The collection, preparation and test process of the convalescent plasma is safe, mature and takes a short time, according to the company.

The company and the Wuhan Blood Center have issued a proposal, calling on cured patients to donate plasma to help other patients who are still in danger.

Convalescent plasma is listed as a therapeutic method in the fifth edition of the COVID-19 diagnosis and treatment plan issued by the National Health Commission.

Zhang Dingyu, head of Wuhan Jinyintan Hospital, also said Thursday that initial results have indicated the effectiveness of plasma transfusion in curing patients diagnosed with COVID-19 infection.