Thousands of people are to be injected with two experimental Ebola vaccines in trials in West Africa within a couple of weeks, and a Baltimore biotechnology company is launching a human trial of its own candidate in June, as scientists and public health officials work to end the deadly epidemic.
The United States is working with Liberia on a study expected to include 27,000 people in that country who are at risk of contracting Ebola. The subjects would receive one of two leading vaccine candidates or a placebo to evaluate the safety and effectiveness of the inoculations. A smaller trial is set for Sierra Leone.
The trials could lead to a faster FDA approval of a vaccine, National Institute of Allergy and Infectious Diseases Director Anthony Fauci said Thursday. But the process could be complicated by the decline in new infections in Africa.
Fauci said the vaccines still could be useful if there's a rebound in Ebola cases — and also for what he called "inevitable" future outbreaks of the virus.
"Unless you extinguish the very last case," Fauci said, "it's not over till it's over."
As other scientists and their investors race to find a safe and effective vaccine, Profectus BioSciences plans to begin testing two vaccines on humans in experiments scheduled to start in June and September. The company has received $32 million in federal backing, and officials say they think their candidate will be competitive with others.
The first trial will test a vaccine designed to help stem the outbreak by offering protection against a virus strain known as Ebola Zaire, said John Eldridge, chief scientific officer for Profectus. The second trial involves a vaccine that the company sees as a longer-term investment, as it would protect against Ebola Zaire, another strain known as Ebola Sudan, and Marburg virus, an organism similar to Ebola that causes hemorrhagic fever.
The company plans to enroll 39 people in the first trial. It is being conducted by Rockville-based contractor Accelovance and its subsidiary, Optimal Research, which is also running human trials of an Ebola vaccine candidate being developed by Johnson & Johnson.
Accelovance helps biotech companies design and conduct clinical trials, said Vice President Michael Keens said, and Optimal Research provides test sites.
Keens said the company has tested vaccines and treatments for pathogens including influenza, dengue fever and anthrax.
Eldridge said he is confident Profectus' triple vaccine will be competitive with others that are racing to gain FDA approval and hit the market.
"Although those [others] are racing forward in an attempt to get a handle on the current outbreak, in my own opinion, the likelihood they will be used long-term is quite small," Eldridge said. "I think when the smoke clears and you step back and take a look at practicality and safety that we have the best combination."
Though infection rates are declining, health officials expect the epidemic to continue through this year. Fauci said the Liberia trial will last nine months to a year. Subjects including health workers, family members of those infected and burial teams are to be randomly assigned to receive a vaccine being developed by the NIH and GlaxoSmithKline, a vaccine being developed by Merck and NewLink Genetics, or a dummy shot.
A second study, using a yet-to-be-determined vaccine candidate, is expected to enroll about 6,000 subjects in Sierra Leone.
In addition to the vaccines, Fauci said scientists also will test the Ebola drug ZMapp in the United States and Liberia. The experimental treatment made headlines last fall when it was given to several Ebola patients last summer, before manufacturer Mapp Biopharmaceutical Inc. ran out of doses. But it has not been formally tested for safety and effectiveness in people, and U.S. officials said there now is enough supply to begin those trials.
The Ebola epidemic has infected more than 21,000 people and claimed more than 8,600 lives, according to the World Health Organization.
Without a proven vaccine, officials have fought the outbreak with old-fashioned public health measures, including isolating the sick, tracking and quarantining those who had contact with them, and employing trained teams to bury bodies safely.
The Associated Press contributed to this article.