Nearly 250 people have died and more than 1,100 infected with a rare Bundibugyo strain of Ebola in the Democratic Republic of Congo and Uganda, prompting non-profit organisations to accelerate vaccine development efforts announced Monday.
This is the 17th Ebola outbreak in the DRC, but only the third caused by Bundibugyo, a strain with no approved vaccines or treatments. Health experts fear the true spread of the virus is much wider than current figures suggest.
The World Health Organization identified a single-dose vaccine using the rVSV platform as the most promising candidate. The same platform underpins the only licensed Ebola vaccine, which targets the more common Zaire strain. The International AIDS Vaccine Initiative reached a deal Monday with the University of Texas Medical Branch to develop the rVSV candidate, led by virologist Thomas Geisbert who pioneered work on both the Bundibugyo and Zaire vaccines. Geisbert's 2013 research showed his jab provided very strong protection against Bundibugyo in monkeys, but the vaccine sat unused for more than a decade due to lack of interest from pharmaceutical firms.
The WHO estimates it will take seven to nine months before the rVSV vaccine is ready for human testing. The Coalition for Epidemic Preparedness Innovations announced Monday that it is funding three Bundibugyo vaccine candidates, allocating $3.2 million to the rVSV jab. WHO chief Tedros Adhanom Ghebreyesus, who visited the outbreak epicentre over the weekend, called the funding "an important step forward".
CEPI also committed $50 million to a messenger RNA vaccine candidate from US pharmaceutical giant Moderna, using technology pioneered in its Covid vaccine. Another candidate backed by CEPI uses the University of Oxford's ChAdOx1 platform, which also underpinned AstraZeneca's Covid vaccine. The Serum Institute of India will manufacture this viral vector jab, which could be ready for clinical trials within two to three months. Researchers at France's INSERM institute published a preprint paper last week calling for trials to test whether the licensed Zaire vaccine could also protect against Bundibugyo.
The Gavi vaccine alliance announced Monday it would make up to $50 million available for Bundibugyo vaccine efforts. "We need to act now to ensure that, once one or more vaccine candidates are ready, manufacturers are in a position to start producing doses at scale," Gavi CEO Sania Nishtar said. IAVI president Mark Feinberg told a press conference that Gavi's commitment could fund production of roughly 500,000 doses. The funding also sends a signal to manufacturers that they can invest without carrying excessive risk, he added.
Deploying vaccines in the vast, remote DRC region presents real obstacles. The outbreak area already faces hunger, malaria, and conflict. The WHO stressed that gaining community trust where vaccines will be tested is essential. Even after trials begin, there is no guarantee the vaccine will work. The Coalition for Epidemic Preparedness Innovations will coordinate with manufacturers over the coming weeks to finalise production timelines and trial protocols.
