How far off is a vaccine for the current strain of Ebola?

GOMA, Democratic Republic of the Congo - The current Ebola outbreak in central Africa has prompted the World Health Organization (WHO) to raise its highest level of concern, with experts warning that there is neither an approved vaccine nor specific treatment for the Bundibugyo strain now circulating.

The situation is the result of failures stretching back years.

What vaccines currently exist against Ebola?

Health experts list three main Ebola vaccines, but the problem is that all of them target the so-called Ebola virus (EBOV) - formerly known as Zaire ebolavirus - within the Ebola virus genus.

Further vaccines, for example against the Sudan Ebola virus (SUDV), "are currently at various stages of development and are in some cases being used in clinical trials," according to the German health body Robert Koch Institute (RKI).

Two further Ebola strains known to be dangerous to humans exist beyond the two already mentioned: Taï Forest and, above all, the pathogen behind the current outbreak - Bundibugyo (BDBV).

How advanced are the vaccines against Bundibugyo?

All vaccines against the Bundibugyo virus are still at the pre-clinical stage, says César Muñoz-Fontela of the Bernhard Nocht Institute for Tropical Medicine (BNITM) in Hamburg.

That means none has yet been tested in humans - not even, as is usually the first step, for safety in a smaller Phase 1 trial.

That's not all: There is also no stockpile of BDBV vaccine doses that could now be tested for safety and subsequently for protective efficacy in humans.

Producing a sufficient quantity of vaccine doses would take weeks to months - even if production could begin immediately, said infectiologist Marylyn Martina Addo of Germany's University Medical Centre Hamburg-Eppendorf.

After the major EBOV epidemic in West Africa in 2014 and 2015, which killed more than 11,000 people, experts had urged that vaccines against all dangerous Ebola strains be tested for safety and then produced in sufficient quantities to be deployable in the event of an epidemic. "Had we been able to do that 10 years ago with prioritized financial resources," says Addo, "we would have been prepared now."

"We need to produce vaccine doses and therapeutics that are at least ready for clinical trials," stresses Muñoz-Fontela. "And this strategy must be implemented before an outbreak, not after one." Beyond acute epidemics, however, there is little interest in such diseases, the expert said.

Do approved vaccines offer any protection against Bundibugyo?

Possibly a little. There is a close relationship between the Ebola virus (EBOV) and the Bundibugyo virus, explains vaccine design specialist Clara Schoeder of the Institute for Drug Development at the University of Leipzig in Germany.

Antibodies produced in response to EBOV vaccines could therefore potentially neutralize the Bundibugyo pathogen - but nobody knows how pronounced such an effect might be.

In a small study published in 2011, three of four rhesus monkeys vaccinated with a so-called rVSV-EBOV preparation survived infection - but all four fell ill.

Muñoz-Fontela warns against deploying EBOV vaccines whose safety is established but whose efficacy against Bundibugyo is unclear. If the vaccine proved to be of limited effectiveness, the hard-won trust in the vaccine that offers strong protection against EBOV could be undermined in the region.

"More evidence is needed for that," says infectiologist Addo. The plan is to additionally test the efficacy of the VSV vaccine against Bundibugyo in the laboratory using serum from people vaccinated with VSV-EBOV.

How can people with Ebola be treated?

Virologist Stephan Becker says there are no specific approved treatments. "But here too there are antibodies that have protected animals against Bundibugyo, though they have not been clinically tested."

Other experts point out that early detection and treatment in a specialised treatment centre is critical for prognosis. "We know that mortality can be significantly reduced through good supportive therapy," says infectiologist Torsten Feldt. "This includes, for example, fluid and electrolyte management, treatment of shock, bleeding and organ dysfunction, the administration of oxygen and the treatment of co-infections."

What role does poverty in the region play?

"Ebola virus outbreaks are driven by human-to-human transmission," says Muñoz-Fontela. Social factors such as refugee flows, poverty and poor living conditions therefore make it easier for the pathogen to spread following an outbreak.

Jean Kaseya, head of the Africa CDC health authority, added that pharmaceutical companies see little commercial opportunity in the Bundibugyo pathogen in Africa. "But believe me, if Bundibugyo were in western countries, the medical countermeasures would exist."

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This story was originally published May 21, 2026 at 3:07 PM.