GENEVA - The best chance for an immediate treatment for Ebola patients in the worst outbreak ever may be readily available, in the blood of survivors.
With experimental drugs in short supply or not ready for use, global health officials are exploring whether the natural immunity survivors gain after they shed the virus can be shared with others.
The idea would be to use their plasma, the part of blood that contains immune system warriors called antibodies, to help fight off the infection.
Some early research suggests using blood from survivors could work. In 1995, during an outbreak in Kikwit, Congo, seven of eight infected people given the therapy survived during an outbreak with an 80 per cent fatality rate.
While lab studies since then have shown conflicting results, the strategy is worth trying again as the current death toll rises, said Dr David Wood, who leads a World Health Organisation team evaluating the approach.
It is a feasible option, Dr Wood said in a phone interview. "We're consulting with the blood operators who have the capability to assist, so that we can get some realistic sense of when this could be available as an option. We'll have that information pretty soon."
The WHO reported that 1,145 people have, as of last Wednesday, died from Ebola in Guinea, Sierra Leone, Liberia and Nigeria since the outbreak began.
The virus carries a terrible toll, causing bleeding from the eyes, ears and nose, with most patients dying from multiple organ failure.
Yet, about 40 per cent of people infected in the current outbreak have beaten the disease, said the WHO. It is that minority that researchers are targeting for a treatment that may not require drugmakers to be involved at all.
Once researchers get the blood, they will test it for other diseases, including HIV and hepatitis, and then separate out the plasma.
Antibodies in plasma are produced by white blood cells in response to foreign invaders in the body. They bind to the microbes, either neutralising them or flagging them for other parts of the immune system to attack.
Dr Mary Kate Hart, an immunology researcher who did early studies of Ebola antibodies for the US Army, said that transfusions from survivors may carry a benefit, especially if given early in the course of the disease, and are likely to be relatively safe.
Dr Kent Brantly, the American aid worker infected with Ebola in Liberia last month, was given such a treatment.
He received a blood transfusion from a 14-year-old survivor, according to aid group Samaritan's Purse. He also received an experimental antibody-based therapy from Mapp Biopharmaceutical.
While Dr Brantly has been improving, it is not known if either the blood transfusion or the treatment called ZMapp aided his recovery, or whether his own immune system fought off the virus.
Last week, the WHO said that unproven drugs and vaccines could ethically be used during the current outbreak, given that there are no approved treatments.
The supply of Mapp's drug has already been exhausted, however, and preventive vaccines may not be available for at least a month.
Blood serum has also been used in outbreaks of Sars and severe influenza, and was associated with a 75 per cent reduction in the risk of death, according to a review study published last month.
"This would be something that countries could try themselves, and it would be much more feasible and much more immediate," said London School of Hygiene and Tropical Medicine infectious diseases professor David Heymann. "But it shouldn't take precedence over outbreak containment."