2 vaccines for Ebola start trials in Liberia
MONROVIA, Liberia — Large-scale human testing of two potential Ebola vaccines got underway in Liberia’s capital Monday, part of a global effort to prevent a repeat of the epidemic that has now claimed nearly 9,000 lives in West Africa.
Yet even as Liberians volunteered to take part, it remains unclear whether either vaccine ultimately will work, and if so, how quickly it could be mass produced. There is currently no licensed treatment for Ebola, a virus that has killed at least 60 percent of even its hospitalized victims.
The studies in Liberia are taking place after smaller tests determined that the vaccines are safe for human use. By comparing them now with a dummy shot, scientists hope to learn whether they can prevent people from contracting the disease.
Both experimental vaccines showed promise in first-stage human safety tests, Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, has said. One was developed by the
National Institutes of Health and is being manufactured by GlaxoSmithKline. The other was developed by Canadian health officials and is licensed to two U.S. companies, NewLink Genetics and Merck.
The vaccine trials come as the three most affected countries — Guinea, Sierra Leone and Liberia — appear to be making strides against the Ebola epidemic first identified in March. The U.N. health agency said last week that the countries had reported fewer than 100 cases in the past week, for the first time since June.
That prompted Chimerix to stop clinical trials of Ebola antiviral drug brincidofovir last week.
“Given the current decline in the number of new Ebola cases in Liberia, study investigators anticipate the need for flexibility in the conduct and design of the trial to address the changing nature of the outbreak,” the NIH said in a statement.
Fewer infections may make it difficult to collect the full array of data normally gathered in clinical trials. Still, safety and immune response results from the West Africa trials, combined with efficacy data from earlier animal studies, may be enough to submit filings for regulatory approval, the NIH said Jan. 22.
While Glaxo’s vaccine was found to be safe and provoked an immune response in a small trial of healthy volunteers in Oxford, England, the antibody and T-cell responses were lower than those observed in monkeys in earlier studies, according to results published in the New England Journal of Medicine on Wednesday.
Early-stage human trials of ZMapp, an experimental treatment made by Mapp Biopharmaceutical Inc., are still scheduled to begin in the U.S. and Liberia in the next few weeks, NIH spokesman Anne Oplinger said.
Besides recruiting thousands of people from the general population, the researchers are making efforts to attract volunteers from groups at greater risk of Ebola infection, such as health care workers and members of burial teams.
The Centers for Disease Control and Prevention said that it’s still deciding which vaccine to use in a trial in Sierra Leone. That study intends to target people at high risk of contracting the virus, the U.S. agency said Monday in an emailed statement.
The NIH-sponsored trial is taking place at the Redemption Hospital in the New Kru Town suburb of Monrovia, Liberia’s capital. Participants must plan to be in Monrovia for a year, and will be reimbursed for transportation costs and missed work. Volunteers will receive one of the vaccines or a placebo in a double-blind study, meaning neither volunteers nor workers will know whether a medicine or a saline solution is administered.
Despite the vaccine study’s promise, authorities must combat fear and suspicion that people could become infected by taking part. Each vaccine uses a different virus to carry non-infectious Ebola genetic material into the body and spark an immune response.
On Sunday in one densely populated neighborhood of Monrovia, musicians sang songs explaining the purpose and intent of the trial in a bid to dispel fears.
B. Emmanuel Lansana, 43, a physician’s assistant, was the first to receive doses Monday. Two shots were administered at different points on his right arm. His wife had expressed apprehension about the vaccine trial, but Lansana said he still wanted to take part.
“From the counseling, all of the reservations I have were explained, my doubts were cleared,” he said in a room where he was being observed for 30 minutes afterward.
Up to 600 volunteers are taking part in the first phase, and trial organizers have said eventually as many as 27,000 people could take part.
“We are targeting about 12 persons for today and hopefully the number will increase as we go along,” Wissedi Sio Njoh, director of operation with the vaccination campaign, said.
The Liberian government’s cooperation with the NIH is a “show of commitment in the battle to conquer the disease that has ravaged the region,” Vice President Joseph Boakai said in a statement.
The World Health Organization says the Ebola epidemic has infected more than 22,000 people and claimed more than 8,900 lives over the past year. Without a 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 setting up teams to safely bury bodies.
The vaccines being tested won’t be an immediate solution, said Bruce Aylward, who is leading the organization’s Ebola response.
“People keep saying we’re going to have a vaccine, but that will be in the middle of the year at the earliest,” he said last week. “We might be able to vaccinate some first responders, but it’s a complete uncertainty. We have no idea if it will confer protection, even though the indications are good.” Information for this article was contributed by Jonathan PayeLayleh, Lauran Neergaard, Maria Cheng and Krista Larson of The Associated Press and by Makiko Kitamura, Elise Zoker and Caroline Chen of Bloomberg News.