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Experimental Ebola Vaccine Successful in First Human Trials

In a recent study, results from human trials on 20 volunteers showed that the vaccine was not only safe in humans, but might support the immune system in fighting off Ebola.
Image via Flickr/Army Medicine

There have been more than 20 separate outbreaks in the nearly 40 years since the Ebola virus was discovered in 1976, but the current spread of the hemorrhagic fever might be the first to finally prompt a fully approved vaccine, according to results from the first set of human trials for one of many experimental treatments being expeditiously tested.

Findings published on Wednesday in the New England Journal of Medicine indicate that a vaccine for the Sudan and Zaire strains — the ones responsible for infecting more than 15,000 people in Liberia, Sierra Leone, and Guinea in the past year — was safe when tested in humans and could potentially support the immune system in fighting off Ebola.


"On safety and on the ability to produce an appropriate immune response we can call this trial an unqualified success, even though it was an early Phase One trial," Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, told the BBC.

"Based on these positive results from the first human trial of this candidate vaccine, we are continuing our accelerated plan for larger trials to determine if the vaccine is efficacious in preventing Ebola infection," he remarked to CNN.

WHO experts decide it is ethical to offer patients experimental Ebola treatments. Read more here.

After quickly pushing the drug through the first phase of clinical testing, National Institutes of Health researchers vaccinated 20 American volunteers with the gene-based treatment, which had already been tested on primates.

All of the vaccines generated antibodies in each of the volunteers, and results indicated that the gene-based vaccine's efficacy is related to dosage. A higher dose proved essential in generating a "more vigorous immune response," according to an article published in the New England Journal of Medicine about the findings.

Despite the promise the research offers, the journal concluded that the study wasn't enough to provide conclusive results.

"There were no major adverse effects, but the sample size (10 persons at each dose level) is too small to draw firm conclusions in this regard," noted the journal article.


Other details such as duration of the vaccine's protection and the role that natural immunity might play are also unclear.

The NIH human trial is one among several underway as a result of calls from the World Health Organization in August for industry players, as well as health agencies and individual countries, to mobilize efforts to develop an Ebola vaccine. Another vaccine targeting the Zaire strain is undergoing trials in Britain, Switzerland, and Mali, a country that has reported eight cases since October.

The experimental vaccine used in the NIH trial was developed by the pharmaceutical company GlaxoSmithKline and fast-tracked in recent months, but the same researchers had put three early-generation potential vaccines through clinical trials between 2003 and 2009. Like many other drugmakers, attempts to develop an Ebola vaccine have often been stalled or shelved. As the West African Ebola outbreak continues to spread, experts have widely attributed the lack of a pre-existing vaccine to the fact that there is little market incentive for a company to take a product like this one through the trial and approval process.

Looking towards a serum from Ebola survivors to aid in outbreak treatment efforts. Read more here.

"There's no money in it and there's a huge liability," Jonathan Moreno, a biomedical ethics professor at the University of Pennsylvania, told VICE News in August. "If you're a drug company, there's no reason, from a market standpoint, to go into a disease like this."


Moreno explained that government subsidies and liability coverage can compensate for the lack of action in the pharmaceutical industry and incentivize drug development.

University of Queensland virologist Dr. Ian Mackay previously told VICE News that we don't have a very responsive vaccine system, instead "we have something that plays chase or catch-up with an outbreak."

"But now we've seen the scale of a particular virus, where a lot of people died and quickly, we had the ability to treat or maybe prevent those infections sitting in a cupboard," Mackay said. "But because there weren't enough people or there wasn't enough money involved earlier on, they didn't get scaled up."

While it's concerning to think of what other potential treatments might be collecting dust in a research lab, the focus of the international community's energy on developing vaccines and treatments could be the only silver lining to develop out of the deadliest Ebola outbreak ever.

Ebola has done what rare infectious diseases in far away countries rarely do — catch the public's attention.

"Ebola was one of a large number of rare and scary diseases, and drug companies can't focus on everything at the same time. This is good because it is focusing the entire scientific and public health community on one disease," University of Reading virologist Dr. Ben Neuman told VICE News. "With all that focus, somebody is probably going to find a way to cramp this one. If it can be done, it will be done."

Follow Kayla Ruble on Twitter: @RubleKB

Image via Flickr