An Ebola
vaccine partly tested in Kenya may be assessed to determine whether it can
protect against a new variant spreading in Uganda and the Democratic Republic
of Congo.
The vaccine,
Ervebo, is already licensed for protection against one type of Ebola virus
known as Zaire ebolavirus. It was developed through international partnerships
and underwent partial testing in Kenya.
Health experts
say they are now considering whether existing vaccine candidates targeting
other Ebola strains could offer any protection against the current outbreak,
which is caused by the Bundibugyo virus.
However, they
caution that effectiveness against this strain is not yet known.
The outbreak
is growing rapidly in both Uganda and the DRC, with global health agencies
warning of a serious public health risk.
More than 500
suspected cases and over 130 deaths have been reported in the Congo, while Uganda has confirmed cases in Kampala.
Gavi, the
Vaccine Alliance, said there are
currently no licensed vaccines for Bundibugyo virus disease. It said existing
Ebola vaccines in the global stockpile are only approved for Zaire ebolavirus.
“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,
adding that deployment would require informed consent from affected
communities.
The World
Health Organization 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 outbreak is particularly concerning due to its spread in
conflict-affected and hard-to-reach areas, complicating surveillance and
response efforts.
The organisation is working with
partners including WHO, Africa Centers for Disease Control, Unicef, the World Bank and Coalition for
Epidemic Preparedness Innovations to assess
vaccine needs and accelerate response measures.
It is also
evaluating emergency financing through its First Response Fund, which was
established after the Covid-19 pandemic
to enable rapid outbreak interventions.
The fund,
which has 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 vaccine candidates still in development. One uses the same
platform as Ervebo but is being adapted for Bundibugyo virus, although no doses
are currently available for trials, which could take six to nine months to
produce.
Another
candidate uses the ChAdOx platform, previously used in Covid-19 vaccines, though it has not yet undergone
animal or human testing for this strain.
Experts say
Ebola vaccination has previously proven highly effective in controlling
outbreaks of the Zaire strain.
A 2025 BMJ
Global Health study found outbreak vaccination reduced cases by 77 per cent and
deaths by 76 per cent on average.
Gavi currently
maintains a global stockpile of 500,000 doses of the Ervebo vaccine, which has
been deployed in four outbreak responses in the Congo, including a 2025 campaign that vaccinated more
than 47,000 people.
Health workers
in the region have also been vaccinated preventively.
As scientists
assess whether existing tools can be adapted for the new strain, health
agencies stress that speed, coordination and evidence-based action will be
critical to preventing further cross-border spread in East Africa.
