The Democratic Republic of Congo has been allocated 70 000 doses of Merck's Ervebo vaccine for Ebola, the World Health Organization said on Thursday, as the country attempts to contain its biggest ever outbreak of the deadly disease.

Last week Congo had requested a release of Ervebo vaccines from the global Ebola virus disease vaccine stockpile, managed by the International Coordinating Group (ICG) on Vaccine Provision, according to WHO.

The health agency said the group allocated 70 000 Ervebo doses for Congo, of which 20 000 shots will be used in a late-stage trial to understand the impact of the vaccine on the Bundibugyo virus.

The ongoing outbreak is caused by the Bundibugyo species of Ebola, which has no approved vaccines or treatments.

"It is not known whether Ervebo may be protective against the Bundibugyo virus in humans," WHO said, stressing the importance of clinical trials to provide important new evidence.

Ervebo is approved to prevent disease caused by the more common Zaire ebolavirus strain.

The number of confirmed Ebola cases in the Democratic Republic of Congo now exceeds 5 000, according to government data.

Congo's 17th Ebola epidemic became the country's biggest on record in late July by case count, with the death toll now at 2 378 — surpassing the previous worst outbreak in 2018-2020.

Earlier this week, WHO's director-general Tedros Ghebreyesus said the Ebola outbreak in eastern Congo remains a global emergency.

The ICG is a partnership between the WHO, the International Federation of the Red Cross and Red Crescent Societies, Médecins Sans Frontières and UNICEF.