Development of Three Ebola Vaccines Targets Bundibugyo Species Amid Escalating Outbreak
Three new vaccines are currently under development to address the rare Bundibugyo species of Ebola virus, which has resulted in nearly 250 fatalities to date.
The International Aids Vaccine Initiative (IAVI), engaged in developing one of these vaccines, has indicated that the outbreak poses a threat to become the most severe on record.
In addition to IAVI, the University of Oxford and pharmaceutical company Moderna are conducting research to create vaccines targeting the Bundibugyo Ebola virus.
The Coalition for Epidemic Preparedness Innovations (CEPI), which is funding each of these groups, emphasized the urgency of the situation by stating that "every day counts".
Currently, there are over 1,000 suspected Ebola cases in the Democratic Republic of Congo (DR Congo), with nine confirmed cases reported in neighboring Uganda.
Concerns are mounting that this outbreak—detected only after it had spread within a conflict zone with limited healthcare infrastructure—could escalate to the scale of the largest Ebola outbreak recorded in West Africa between 2014 and 2016. That outbreak infected nearly 29,000 individuals and caused more than 11,000 deaths.
Dr. Mark Feinberg, head of IAVI, remarked on the severity of the current situation:
"I think this is clearly threatening to be as severe an outbreak as that, if not even worse, and development of a vaccine, and other countermeasures, is clearly a priority."
These concerns are echoed by the medical charity Médecins Sans Frontières (MSF), which described the situation as "deeply alarming" and noted that "never before had so many cases" been recorded so early in an outbreak.
Vaccine Development Specific to Ebola Species
Vaccines must be tailored to each individual Ebola species. Of the six known species, only three have been associated with outbreaks.
There is an existing vaccine for the most common Zaire species; however, the current outbreak is caused by the Bundibugyo species, which has been documented only twice previously and for which no approved vaccine exists.
IAVI is developing a modified version of the Zaire Ebola vaccine aimed at combating Bundibugyo. This experimental vaccine has been tested in non-human primates, where it rapidly stimulated the immune system and provided nearly 100% protection.
Dr. Feinberg expressed cautious optimism regarding the vaccine's potential, stating:
"Our evidence so far means I am optimistic about the potential,"
but he also noted that it would currently take seven to nine months to prepare the vaccine for clinical trials, although efforts are underway to "accelerate those timelines."
Meanwhile, Moderna has announced its use of mRNA technology—previously deployed to rapidly develop Covid-19 vaccines—to develop a vaccine targeting Bundibugyo.
Stéphane Bancel, CEO of Moderna, stated:
"We will move with urgency and scientific rigor to support the response and help bring a potential vaccine closer to the communities that need it most."
The University of Oxford is also developing its own vaccine using technology that contributed to Covid-19 vaccine development. Oxford anticipates readiness for clinical trials within two to three months.
Vaccine Mechanisms and Immune Response
Each vaccine candidate aims to train the immune system to recognize the Bundibugyo glycoprotein, a structure on the virus surface. However, each employs a distinct technological approach.
IAVI’s vaccine uses a live but harmless virus engineered to express the Ebola glycoprotein. The immune system combats this harmless virus and, in the process, learns to recognize and fight Ebola.
Both the mRNA vaccine by Moderna and the Oxford vaccine deliver genetic code snippets into the body. These snippets instruct cells to produce the Bundibugyo glycoprotein, which the immune system identifies as foreign and attacks.
All three approaches aim to provide the immune system with a preparatory advantage against actual Ebola infection.
Differences in vaccine technologies and immune training methods may influence the level of protection and the number of doses required. These factors necessitate evaluation through clinical trials.
Funding and Global Health Perspectives
The Coalition for Epidemic Preparedness Innovations (CEPI) is financing the early research phases for all three vaccines.
Dr. Richard Hatchett, CEO of CEPI, emphasized the urgency:
"With Bundibugyo virus spreading rapidly and no licensed vaccines, every day counts in the race against this deadly disease."
Dr. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization, commented:
"A Bundibugyo vaccine could help to control this epidemic and strengthen preparedness for future outbreaks."
