The U.S. government will soon begin testing the effectiveness of two experimental Ebola vaccines in health care workers and the general population of Liberia and Sierra Leone in West Africa.
Because no drugs have been proven safe and effective in the specific treatment Ebola, the Obama administration - through the National Institutes of Health, the Department of Health and Human Services and the Food and Drug Administration - is working to accelerate the approval, testing, production and distribution of potential Ebola treatments and vaccines.
One promising vaccine candidate, developed by GlaxoSmithKline and NIH, uses a chimpanzee virus to introduce Ebola virus genes into the body where they stimulate an immune response against the virus itself. It has shown promising results in humans and animals against the Zaire Ebola species wreaking havoc in West Africa.
Clinical trials will also begin on another experimental vaccine developed by the Public Health Agency of Canada with support from the U.S. Department of Defense. NewLink Genetics, of Ames, IA. and the drug maker, Merck, have partnered on further development of this vaccine candidate.
"The next step is to determine efficacy of both of these vaccine candidates in addition (to) further proof of safety," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the NIH.
"Our hope is that (the vaccines) could be licensed and used in the field to protect front line health care workers as well as people living in areas where Ebola viruses exist," Fauci said in a telephone briefing with reporters on Thursday.
The plan is to conduct a "randomized double-blind controlled trial," which is considered the gold standard for pharmaceutical testing, Fauci said. Trial volunteers will either get injected with doses of a placebo or one of the two vaccine candidates, Fauci said.
Participants will be drawn mainly from those at highest risk for contracting the virus. This includes health care workers, burial team members, household contacts of Ebola patients and contact tracers, who scour West Africa looking for people who may have had contact with confirmed Ebola patients.
An estimated 27,000 people are expected to participate in the Liberia study which could take 9 months to a year to complete, Fauci said.
Another clinical trial set to begin within a month in Sierra Leone will compare the disease risks between those who received one of the experimental vaccines early and those who were vaccinated later in the study.
"Which vaccine will be used hasn't been finalized, but we're working closely with colleagues to review the emerging data on safety, immune response and the practical logistical considerations for the country," said Dr. Anne Schuchat, director of the CDC’s National Center for Immunization and Respiratory Diseases.
An estimated 6,000 people are likely to participate in the Sierra Leone study which will also target health care workers and civilians who are at higher risk for contracting Ebola.
In spite of the ramped-up effort, manufacturers don’t expect meaningful amounts of promising Ebola vaccines and treatments to be available to the general public for months, even years.
Officials at GlaxoSmithKline have said their Ebola vaccine candidate won’t be ready in time to provide any significant relief for the current outbreak.
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