The World Health Organisation (WHO) says it is exploring possible experimental vaccines against the rare Bundibugyo strain of Ebola as deaths continue to rise in ongoing outbreaks in the Democratic Republic of Congo (DRC) and Uganda, where no approved vaccine currently exists for the virus species.
WHO officials disclosed this on Thursday during a regional briefing convened by the WHO Regional Office for Africa (WHO AFRO), where health experts highlighted the risk of cross-border transmission.
Speaking during the briefing, Otim Ramadan, Health Emergency Officer at WHO, said there is currently no approved vaccine or therapeutic specifically for the Bundibugyo strain, unlike the Ebola Zaire species for which vaccines were successfully developed after the 2014–2016 West Africa outbreak.
He explained that among the Ebola viruses known to cause outbreaks in humans, Ebola Zaire, Sudan virus and Bundibugyo virus, the Zaire species has been the most common and the most researched because of the scale of previous outbreaks.
Ramadan said the WHO is now engaging vaccine developers and researchers globally to determine whether experimental or “candidate vaccines” can be deployed under strict clinical trial protocols as part of the emergency response.
He disclosed that the WHO’s Research and Development Blueprint team is already coordinating global scientific engagements on possible vaccines and therapeutics.
“I know tomorrow we have a global scientific conference looking at therapeutics and research generally into vaccines and therapeutics with different researchers to try to see what candidate vaccines are available,” he said.
According to him, the current outbreak is only the third recorded outbreak linked to the Bundibugyo strain globally. The first occurred in Uganda in 2007, while the second was recorded in Isiro, DRC, in 2012.
The development comes as the outbreak worsens across affected countries. According to WHO updates released on May 20, suspected cases linked to the outbreak rose to 575 from 246 within the same reporting period, while deaths increased from 80 to 148.
WHO data further showed differences in fatality rates between affected countries. In the DRC, the crude case fatality rate currently stands at 7.8 %, while Uganda’s fatality rate has climbed to 50%.
Marie-Roselyne Belize, WHO Regional Emergency Director, represented at the briefing by Ramadan, warned that the outbreak once again demonstrates how infectious diseases easily spread across national borders through the movement of people and goods.
“The outbreak reminds us once again that outbreaks do not respect borders,” she said.
She stressed that no country can respond alone and called for stronger regional coordination, timely information sharing and improved surveillance systems to contain the outbreak before it spreads further.
According to her, countries must strengthen screening and preparedness at points of entry in line with the International Health Regulations (IHR), while ensuring rapid laboratory confirmation, stronger infection prevention measures and community engagement.
Belize also warned that coordinated action would be critical not only to protect public health but also to prevent disruptions to trade and travel across the region.
“It’s an important moment for coordinated action to prevent further spread and protect the health and safety of populations while ensuring there is no interruption to trade and travel,” she said.
