Two South Koreans with severe symptoms of the coronavirus have recovered from pneumonia after receiving treatment using plasma from two other survivors, according to a new report.

The two patients, both over the age of 65, responded to the plasma treatment after other therapeutic methods did not work, Agence France-Presse reported.

Plasma therapy is "important" when there was "currently no vaccine or treatment available," Kwon Jun-wook, an official at Seoul's Central Disease Control Headquarters, told the news outlet.

Some scientists have pointed to using plasma from people who have developed antibodies to the virus as a possible treatment. The Food and Drug Administration approved the first coronavirus antibody test in the United States last week.

More than a million cases of the virus have been confirmed worldwide.

