A vaccine that protected monkeys from the Bundibugyo strain of ebola in 2011 has never been advanced to human trials or deployed, even as a current outbreak in Central and East Africa has infected hundreds and killed approximately 200 people, according to a report by WIRED. Virologist Thomas Geisbert, an immunology professor at the University of Texas Medical Branch in Galveston, developed the vaccine using recombinant vesicular stomatitis virus (rVSV) technology to deliver genetic instructions to fight the disease. Geisbert stated, "We've got the rVSV Bundibugyo vaccine sitting on the shelf."
Background of the Vaccine
Geisbert's work began in the early 2000s as a defense project funded by the US Army after September 11, due to concerns about bioterrorism. His first major breakthrough came in 2003, when a single injection of his vaccine protected monkeys from ebola. However, after publishing his findings a few years later, he found little commercial interest. "There just wasn't a global market for an ebola vaccine," Geisbert told WIRED. "It's not a moneymaker, nobody really wanted to pick it up."
In 2009, Geisbert tested a blend of vaccines against three of the four ebola viruses known to harm humans, with success. This made the vaccine cheaper and easier to mass-produce. However, the Bundibugyo strain — which has lower fatality rates and caused only three outbreaks — was omitted from that study. "We thought that's probably the one that's least likely to pop up," Geisbert said. "We guessed wrong."
The 2011 Monkey Study
Concerned by that knowledge gap, Geisbert modified the vaccine in 2011 and tested it on crab-eating macaques in a high-containment laboratory on an island off Texas. The monkeys were infected with the newly discovered Bundibugyo strain. The three vaccinated monkeys showed no symptoms, while two-thirds of the unvaccinated companions died from symptoms including fever, weight loss, rectal bleeding, and nosebleeds. Scientists in space suits drew blood to monitor immune responses.
Why It Remains on the Shelf
Despite the vaccine's proven efficacy in primates, it has not been tested in humans or deployed. Interest in ebola vaccines surged during the 2013–2016 epidemic, when the Zaire strain infected 28,600 people and killed 11,300 in West Africa. That crisis led to the development of Ervebo by pharmaceutical giant Merck, partly based on Geisbert's earlier work. Ervebo was deployed in a "ring" vaccination strategy, creating buffer zones that limited spread. Geisbert's success earned him a spot among Time magazine's "ebola fighters" as People of the Year in 2014.
However, the Bundibugyo-specific vaccine never received funding for human trials. The World Health Organization has identified Geisbert's vaccine as the most promising candidate for the current outbreak, but it could take months to test safety and efficacy. Geisbert noted that even with the outbreak, there has not been sufficient funding or interest to move the vaccine forward.
Production Timeline
No production timeline exists for the rVSV Bundibugyo vaccine. It remains in laboratory storage, awaiting funding to begin human trials and eventual manufacturing. The current outbreak continues to spread, with the vaccine still on the shelf.
Implications for Pharmaceutical Manufacturing
For manufacturing executives and procurement directors, the story underscores the challenge of aligning vaccine development with commercial viability. The rVSV platform used by Geisbert is a single-injection technology that could be scaled if funding emerges. However, without a clear market signal or public-health investment, even a promising vaccine can languish for 15 years. The case highlights the need for public-private partnerships to de-risk production of vaccines for rare but deadly pathogens.
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