survivors of the virus, the World Health Organization warned.
The deadliest Ebola outbreak in history has killed at least 2,400 people in Guinea, Liberia and Sierra Leone -- the countries most affected by the virus.
Thousands more are infected, and new cases have emerged in Nigeria and Senegal.
Blood from survivors, referred to as convalescent serum, is said to have antibodies that can fight the deadly virus. Though unproven, it has provided some promise in fighting a disease with no approved drug to treat it.
"Studies suggest blood transfusions from survivors might prevent or treat Ebola virus infection in others, but the results of the studies are still difficult to interpret," the WHO said.
"It is not known whether antibodies in the plasma of survivors are sufficient to treat or prevent the disease. More research is needed."
Convalescent serum has been used to treat patients, including American aid worker Rick Sacra, who is hospitalized in Omaha, Nebraska. He got blood from Kent Brantly, a fellow American who survived Ebola. Both got infected when they were helping patients in Liberia.