A World Health Organization-led panel of health experts met on Tuesday to consider possible vaccine and treatment options for an Ebola outbreak in eastern Democratic Republic of Congo, where more than 500 suspected cases have been recorded.
The outbreak, involving the rare Bundibugyo strain of Ebola, has been linked to more than 130 suspected deaths, according to the WHO. The agency and the Africa Centres for Disease Control and Prevention have both declared the outbreak a public health emergency.
There are currently no approved vaccines or treatments specifically for the Bundibugyo strain, which can have a fatality rate of up to 40%.
Experts are expected to assess whether existing Ebola vaccines could be tested or deployed in response to the outbreak. One option under review is Merck’s Ervebo vaccine, which is approved for the Ebola Zaire strain and has shown some evidence of protection against Bundibugyo in animal studies.
The WHO Technical Advisory Group is also expected to discuss possible treatment options. Any final decision on vaccine trials or emergency use would rest with authorities in Congo and neighbouring Uganda, where two confirmed cases have also been reported.
“When you have an outbreak with a strain that does not have countermeasures, we are going to advise on the best approach to take,” said Dr Mosoka Fallah, acting director of the science department at Africa CDC. “We will look at what evidence we have and make a decision.”
Gavi, the global vaccine alliance, maintains a stockpile of Ebola vaccines. Its chief executive, Sania Nishtar, said 2,000 doses were already in Congo and could be used if experts recommend a trial.
But health officials and vaccine experts warned that controlling the outbreak could prove difficult, particularly because of insecurity in eastern Congo.
“Our concern about this outbreak is pretty high,” said Richard Hatchett, head of the Coalition for Epidemic Preparedness Innovations, which funds vaccine development and is examining potential candidates.
Hatchett noted that the 2018-2019 Ebola outbreak in the same region, caused by the Zaire strain, took two years to bring under control despite the availability of an approved vaccine.
“The security situation is very serious, and so testing things in clinical trials will be challenging, but will be necessary as well,” he said.
Courtney Woolsey, an assistant professor at the University of Texas Medical Branch, said there were “substantial” obstacles to moving a Bundibugyo-specific vaccine toward emergency or clinical use.
“From a regulatory standpoint, Bundibugyo outbreaks are rare and unpredictable, which makes traditional efficacy trials difficult,” Woolsey said.
The outbreak has renewed concerns over gaps in Ebola preparedness, particularly for less common strains that lack approved countermeasures.
