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The quest to develop an Ebola vaccine took a small but significant step forward as regulators on both sides of the Atlantic agreed to conduct speedier reviews of a treatment being developed by Merck.

The US Food and Drug Administration granted what is known as a breakthrough therapy designation for the Merck vaccine, a status reserved for medicines designed to treat a serious or life-threatening illness. At the same time, the European Medicines Agency granted the vaccine Prime status, which refers to a treatment targeting an unmet medical need.

The moves come as Merck looks to gather data from three separate clinical trials and submit the information later this year to regulators in hopes of winning approval to market and distribute its vaccine by the end of 2017.


Three major studies are being led by public health officials in different African countries, a Merck spokeswoman noted. The World Health Organization is leading one study in Guinea, while the US National Institutes of Health is leading another in Sierra Leone and the US Centers for Disease Control and Prevention is heading yet another study in Liberia.

Last year, interim results from the study being conducted in New Guinea showed that the Merck vaccine, which is referred to as both VSV ZEBOV and V920, demonstrated the ability to cut the risk of infection in people. GlaxoSmithKline is also a running late-stage test to determine whether its own vaccine is effective against Ebola.


In recent months, concerns over Ebola have been eclipsed by the spread of the Zika virus. Nearly 30,000 people were afflicted with Ebola, and more than 11,000 died as a result of the outbreak that began two years ago. Since then, the disease appears to have largely been contained, although health officials still worry about new outbreaks.

Meanwhile, there are concerns that Zika transmission may spread rapidly as people flock to the upcoming Olympic games in Brazil, although the CDC believes this worry pertains to just a few countries. Meanwhile, the CDC earlier this month reported that a New York woman who contracted Zika marked the first time that the virus was known to have passed from a woman to a male sex partner.

The Merck vaccine was initially developed by the Public Health Agency at Canada’s National Microbiology Laboratory and licensed to NewLink Genetics. In late 2014, when the Ebola outbreak peaked in Western Africa, Merck licensed the vaccine from NewLink Genetics.

Merck, by the way, has also applied to the WHO for emergency use assessment, but has not yet heard back from the agency, the spokeswoman said.  This step would allow use of the vaccine if an international public health emergency is declared before the treatment is licensed by regulators.