NAIROBI, Kenya — An Ebola vaccine partly tested in Kenya could be assessed to determine whether it offers protection against a new strain spreading in Uganda and the Democratic Republic of Congo (DRC).
The vaccine, Ervebo, is already licensed for protection against the Zaire strain of the Ebola virus and was developed through international research partnerships, with parts of its evaluation conducted in Kenya.
Health experts say ongoing discussions are focused on whether existing vaccine candidates designed for other Ebola species could provide any level of cross-protection against the current outbreak, which is caused by the Bundibugyo virus.
However, they caution that there is currently no confirmed evidence that the vaccine is effective against this strain.
The outbreak has expanded in both Uganda and the DRC, with global health agencies warning of a heightened public health risk.
More than 500 suspected cases and over 130 deaths have been reported in the DRC, while Uganda has confirmed infections in Kampala.
The Gavi, the Vaccine Alliance said there are currently no licensed vaccines for Bundibugyo virus disease, noting that existing Ebola vaccines in global stockpiles are approved only for the Zaire strain.
“Considering the extremely limited available evidence on cross-protection against non-Zaire species, any decision to use this vaccine in the current outbreak will require further assessments and will occur in accordance with WHO guidance,” Gavi said.
The organisation added that any deployment would require informed consent from affected communities.
The World Health Organization (WHO) has declared the outbreak a Public Health Emergency of International Concern, while the Africa Centres for Disease Control and Prevention has classified it as a continental emergency.
Gavi warned that the situation is particularly concerning due to the spread of infections in conflict-affected and hard-to-reach areas, which complicates surveillance and response operations.
It is working alongside partners including WHO, Africa CDC, Unicef, the World Bank and the Coalition for Epidemic Preparedness Innovations to assess vaccine needs and accelerate response efforts.
The alliance is also evaluating emergency financing through its First Response Fund, created after the Covid-19 pandemic to support rapid outbreak containment.
The fund, which has about Sh64.75 billion available through 2030, was recently used during an mpox outbreak to secure 500,000 vaccine doses and support a Sh1.29 billion response operation.
Gavi said it is also reviewing experimental vaccine candidates still in development.
One candidate uses a platform similar to Ervebo but is being adapted specifically for the Bundibugyo virus. However, no doses are currently available for trials, and production could take six to nine months.
Another candidate is based on the ChAdOx platform, previously used in Covid-19 vaccines, though it has not yet undergone animal or human testing for this strain.
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Experts note that Ebola vaccination has previously been highly effective in controlling outbreaks of the Zaire strain.
A 2025 BMJ Global Health study found that outbreak vaccination reduced cases by 77 per cent and deaths by 76 per cent on average.
Gavi maintains a global stockpile of about 500,000 doses of Ervebo, which has been deployed in multiple outbreak responses in the DRC, including a 2025 campaign that vaccinated more than 47,000 people.
Health workers in affected regions have also received preventive vaccination.
As scientists assess whether existing tools can be adapted for the new strain, health agencies stress that speed, coordination and evidence-based decision-making will be critical to containing cross-border spread in East Africa.
