By Jack Kim SEOUL (Reuters) – Two South Korean hospitals are conducting experimental treatment on Middle East Respiratory Syndrome (MERS) patients, injecting them with blood plasma from recovering patients, the health ministry said on Tuesday, as four new cases were reported. The procedure has been conducted on two consenting MERS patients in addition to existing care, the ministry's head of public health policy, Kwon Jun-wook, told a media briefing. “There is insufficient clinical basis about the result of plasma treatment among experts in the country,” Kwon said, but added: “The ministry has deep confidence in the medical staff on the direction of the treatment.” Plasma treatment was previously used in SARS patients with some positive results in seriously ill patients that led to a decrease in the death rate by up to 23 percent, Kwon said.