Ebola Survivor Blood Trial May Move as New Cases in Liberia Wane

A clinical trial using blood from Ebola survivors to treat patients in Liberia may not be able to proceed or may have to move to Sierra Leone because there are too few cases of the deadly virus to assess the treatment’s effectiveness, according to two people familiar with the matter.

A basic agreement has been reached to move the trial, which is backed by the Bill & Melinda Gates Foundation, though researchers are concerned it may run into the same problem. While there are more cases in Sierra Leone, the number there is dropping as well, the people said, asking not to be identified because no final decision has been made.

While the receding epidemic is good news, it may leave researchers without answers about whether experimental treatments and vaccines work. Anecdotal evidence from previous Ebola outbreaks suggested that antibodies in survivors’ blood may help other patients fight off the deadly virus, though no trial has ever been done to test the theory.

The Gates Foundation said in November it was providing funding for the trial, which was built on the assumption that demand to join the tests would exceed the supply of survivor blood. Instead the reverse has happened, one of the people said.

The Ebola virus has infected 21,759 people and killed 8,668 in Liberia, Sierra Leone and Guinea, according to the World Health Organization. Still, only eight cases of Ebola were reported in Liberia last week, compared with more than 300 a week in September. Guinea reported 20 cases while Sierra Leone remains the worst-affected country with 117 cases last week.