The First FDA-Approved Ebola Vaccine: Another Animal Research Victory

On Thursday, December 19, 2019, the FDA announced the approval of Ervebo, the first FDA-approved vaccine for the prevention of the Ebola virus disease. The new vaccine protects against the Zaire species of Ebola virus, which is responsible for more than 11,000 deaths in West Africa between 2014 and 2016, and over 2,200 deaths in the Democratic Republic of the Congo (DRC) since 2018. Animal research was involved in many steps that led to the discovery, development and approval of the Ervebo vaccine. Animal models are also integral to research currently underway to treat patients infected with Ebola as well as research to understand the zoonotic transmission of Ebola from animals to humans to prevent future outbreaks.

In the 2000s, Heinz Ulrich Feldmann, MD, PhD, then-Chief of the Special Pathogens Program at the Public Health Agency of Canada’s National Microbiology Laboratory in Winnipeg, and his collaborator Tom Geisbert, PhD, then-Chief of the Department of Viral Pathology and Ultrastructure at the U.S. Army Medical Research Institute of Infectious Diseases in Frederick, Maryland, injected mice in their laboratories with a vesicular stomatitis virus (VSV) vector containing the Ebola glycoprotein to see if the modified vector would vaccinate the mice for the Ebola virus. The approach proved successful and the mice became immunized against the Ebola virus.

Next, Dr. Geisbert replicated the mice study in non-human primates in his laboratory. Like the mice, the non-human primates did not contract the Ebola virus. Thanks to this research, it was determined that the VSV vector loaded with the Ebola glycoprotein could be used as the foundation for an effective Ebola vaccine. The Canadian government awarded $2 million to the National Microbiology Laboratory in Winnipeg to produce vials of human-grade VSV for Ebola, but without much interest from pharmaceutical companies, the Ebola vaccine’s development paused there.

When the World Health Organization (WHO) declared the Ebola outbreak in West Africa a global health emergency in 2014, the Canadian government donated the Ebola vaccine to the agency. In a noteworthy example of public-private partnerships, the WHO facilitated international coordination among academic institutions, the pharmaceutical industry, policy-makers, and biodefense research organizations to get the vaccine through expedited phase 1 and phase 2 clinical trials in the U.S., Europe, and Africa to determine if the pre-clinical vaccine results in non-human primates could be replicable in humans.

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By the fall of 2014, the pharmaceutical company Merck had obtained the license for the vaccine, and phase 3 vaccine clinical trials began in earnest in Liberia, Sierra Leone, and Guinea. Results from the Guinea phase 3 trial were strong enough to convince Merck to move forward with the production of the vaccine, called Ervebo. When the DRC Ebola outbreak broke out in 2018, the DRC used Merck’s Ervebo vaccine under a compassionate use protocol to vaccinate more than 260,000 people. A year later, the European Commission and the FDA approved the Ervebo vaccine for use in Europe and the U.S.

On Sunday, December 29, 2019, National Institutes of Health Director Francis Collins, MD, said on the weekly C-SPAN News Makers program: “How did we get to the point where we are right now, where we have an effective treatment for Ebola virus? … We now have effective treatments because we were able to try them out on non-human primates who also get this disease.” Collins’ quote illustrates the importance of animal research to fight and prevent disease outbreaks like Ebola.