In 2005, a single intramuscular injection of the EBOV or MARV vaccine was found to induce completely protective immune responses in nonhuman primates (crab-eating macaques) against corresponding infections with the otherwise typically lethal EBOV or MARV.In 2010, PHAC licensed the intellectual property on the vaccine to a small U.S. company called Bioprotection Systems, which was a subsidiary of Newlink Genetics, for US $205,000 and "low single-digit percentage" royalties. Newlink had funding from the U.S. Defense Threat Reduction Agency to develop vaccines.In December 2013, the largest-ever Ebola epidemic started in West Africa, specifically, in Guinea. On August 12, the WHO ruled that offering people infected with Ebola the RVSV-ZEBOV vaccine (which at the time was untested on humans) was ethical, and the Canadian government donated 500 doses of the vaccine to the WHO. In October 2014, Newlink had no vaccine in production and no human trials underway, and there were calls for the Canadian government to cancel the contract. In September or October 2014, Newlink formed a steering committee among the interested parties, including PHAC, the NIH, and the WHO, to plan the clinical development of the vaccine.In October 2014, Newlink Genetics began a Phase I clinical trial of rVSV-ZEBOV on healthy human subjects to evaluate the immune response, identify any side effects and determine the appropriate dosage. Phase I trials took place in Gabon, Kenya, Germany, Switzerland, the US, and Canada.
The committee found that under an intention-to-treat analysis, the rVSV-ZEBOV vaccine might have had no efficacy, agreed with the authors of the December 2016 report that it probably had some efficacy, but found statements that it had substantial or 100% efficacy to be unsupportable.In April 2019, following a large-scale ring-vaccination scheme in the DRC outbreak, preliminary results showed that the vaccine had been 97.5% effective at stopping Ebola transmission, relative to no vaccination.In September 2019, the U.S. Food and Drug Administration (FDA) accepted Mercks Biologics License Application and granted priority review for the vaccine.In October 2019, the European Medicines Agency (EMA) recommended granting conditional marketing authorization for the rVSV-ZEBOV-GP vaccine.In November 2019, the European Commission granted a conditional marketing authorization to Ervebo and the World Health Organization (WHO) prequalified an Ebola vaccine for the first time, indicating that the vaccine met WHO standards for quality, safety and efficacy, and allowing UN agencies and GAVI to procure vaccine for distributions.In December 2019, Ervebo was approved for use in the United States.The approval of Ervebo was supported by a study conducted in Guinea during the 2014-2016 outbreak in individuals 18 years of age and older. The study was a randomized cluster (ring) vaccination study in which 3,537 contacts, and contacts of contacts, of individuals with laboratory-confirmed Ebola virus disease (EVD) received either "immediate" or 21-day "delayed" vaccination with Ervebo.