Bundibugyo Ebola Vaccine Candidate Moves Toward Clinical Trials
- An experimental vaccine candidate targeting the Bundibugyo ebolavirus strain is advancing toward clinical trials, according to the World Health Organization.
- There are currently two potential vaccine candidates for the Bundibugyo strain, though neither is ready for human testing, according to Dr.
- A second candidate might be available in two to three months, but it lacks supporting results in animal studies.
An experimental vaccine candidate targeting the Bundibugyo ebolavirus strain is advancing toward clinical trials, according to the World Health Organization. However, the World Health Organization cautioned that human testing remains months away.
Development Timeline for Bundibugyo Candidates
There are currently two potential vaccine candidates for the Bundibugyo strain, though neither is ready for human testing, according to Dr. Vasee Moorthy, lead for the WHO’s research and development blueprint. Speaking during a news conference, Moorthy stated that the more promising candidate could require six to nine months before enough doses are ready for trials.
A second candidate might be available in two to three months, but it lacks supporting results in animal studies. Moorthy noted that progression will depend entirely on incoming animal data to determine if the formula is a viable candidate for the strain.
Evaluating Existing Zaire Strain Vaccines
The extended timeline has prompted health officials to examine alternative options, including Merck’s established Ebola vaccine, Ervebo. Ervebo targets the Zaire strain, which is the most common and deadliest type of the virus, but animal studies suggest it might offer limited cross-protection against the Bundibugyo type.
Moorthy emphasized that Ervebo is not a vaccine specifically for Bundibugyo, though a formal review is underway to see if it can help mitigate ongoing outbreaks. A 2011 study published in the Journal of Infectious Diseases evaluated an early version of Ervebo in macaques exposed to the Bundibugyo virus.
Geisbert cautioned that the actual protection rate might be close to 50% when accounting for animals that could have survived without the intervention. He described the statistical power of those nonhuman primate studies as limited due to small sample sizes.
Public Health Context and Containment Measures
Global health agencies previously found little demand for a specific Bundibugyo vaccine because past outbreaks were rare, small, and relatively easy to contain, according to Dr. Geeta Sood, a hospital epidemiologist at Johns Hopkins Bayview Medical Center. Sood noted that the Bundibugyo virus carries a mortality rate of approximately 25% to 40%, which is lower than the 50% to 60% average seen in other Ebola types.
While awaiting viable vaccines for the strain, relief organizations must rely on foundational response protocols. Alan Gonzalez, deputy director of operations at Médecins Sans Frontières, also known as Doctors Without Borders, stated that responders must return to basics, focusing on contact tracing, patient identification, safe isolation, and strict infection prevention and control across all operational sites.