Federal officials and pharmaceutical companies are planning in the near future to start two large clinical trials of Ebola vaccines in West African countries devastated by the outbreak, a government official said Thursday.
The trials will run separately — one in Liberia, the other in Sierra Leone — and involve different designs to ensure at least one produces usable information.
Treating Ebola: The Hunt for a Drug
Although there are currently no drugs or vaccines approved in the United States to treat or prevent Ebola, health officials have used several experimental drugs in the recent epidemic.
“It’s very important to make sure that, given how challenging these trials might be, that we take no chances, that we have more than one trial going on,” this official said, speaking on condition of anonymity because the studies have not been formally announced.
The World Health Organization held a meeting in Geneva on Thursday involving governments, pharmaceutical companies and charities, among others, to discuss Ebola vaccine trials. Conclusions of the meeting are expected to be announced Friday.
W.H.O. officials said earlier this week that trials of two vaccines furthest along in development would start in West Africa as early as January. But the details have not been known.
Participants will be people at high risk of infection, including health care workers and possibly others, including burial workers and those caring for family members with the disease.
The trials will be challenging because health care systems in countries with Ebola are breaking down. And there are sensitive issues such as whether to give some participants a placebo. A placebo-controlled trial can produce the quickest answers about whether a vaccine works, experts say. But some critics have said it is unethical to offer people placebos instead of a vaccine that might save their lives.
One trial will test the two vaccines against each other and against a control. One-third of participants will receive a vaccine being developed by GlaxoSmithKline. Another third will receive a Canadian vaccine licensed to NewLink Genetics. The rest will get a vaccine for a disease other than Ebola, such as flu — essentially a placebo in terms of preventing Ebola infection.
That trial will probably involve about 9,000 people in each segment, the official said. It will take place in Liberia under the auspices of the National Institutes of Health and Liberia’s Health Ministry.
For the other trial, everyone at a particular site, such as a treatment center, will be offered a vaccine. Different centers will offer vaccines at different times. In that design, no one gets a placebo. That study will take place in Sierra Leone and is being planned by the Centers for Disease Control and Prevention.