With Ebola nearly eliminated in West Africa, vaccine trials probably will fail to provide enough useful data on how well they protect people against the virus, the World Health Organization (WHO) said.
Liberia was declared free from Ebola by the government and the WHO recently after 42 days without a new case of the virus, which killed more than 4,700 people there during a year-long epidemic.
Guinea reported seven cases in the week of May 4-10, while Sierra Leone had two, Dr. Marie-Paule Kieny, WHO Assistant Director-General for Health Systems and Innovation, told a news briefing in Geneva.
“The best news is we are going to zero cases, there is absolutely no doubt about that,” she said in a Reuters article.
Two experimental Ebola vaccines – developed by GlaxoSmithKline and jointly by Merck and NewLink Genetics – being tested on volunteers may not provide much information about effectiveness as the case numbers decrease, Kieny said.
“It is not clear whether it will be possible to have even a hint of efficacy from these two vaccines,” she continued, noting that they already had been proven safe.
“To have efficacy we must see if people are actually protected; as the number of cases is going down it is not clear whether there will be a strong robust answer to this question at the end of the epidemic,” she told Reuters.
Two other drugs – Zmapp made by Zmapp Pharmaceuticals and sIRNA by Tekmira Pharmaceuticals – also are being tested and researchers hope that they will produce some limited results on efficacy, Kieny added.