Trials for a vaccine for the Bundibugyo strain are ongoing, as DRC authorities try to control the Ebola outbreak.

The Democratic Republic of Congo (DRC) has begun vaccinating people against Ebola, with health workers and other front-line workers being prioritised.

However, the vaccine being distributed this week is licensed for another strain, and its effectiveness against the Bundibugyo strain of Ebola has not been determined.

There is currently no approved vaccine or treatment for the new strain, and clinical trials are ongoing to find a suitable vaccine for the Bundibugyo strain.

The first injections are being given to health workers in the Congolese city of Kisangani.

More than 50,000 doses of the vaccine have been received, according to the Congolese health minister, Samuel Roger Kamba.

The outbreak is concentrated in the Ituri province, which borders Uganda.

Kamba said: “We will cover all the provinces that are around Ituri, moving in the ring towards the centre of the outbreak.”

The World Health Organization (WHO) said last week that 70,000 doses of the Ervebo vaccine had been approved for use in the DRC.

About 20,000 of the doses allocated to the DRC will be used in a clinical trial to test its effectiveness against the latest strain. Health workers are calling for more doses.

As of Tuesday, the DRC had recorded 5,713 confirmed cases of Ebola, including 2,744 deaths, according to government figures. The outbreak is the deadliest of all past Ebola outbreaks that have hit the DRC.

The outbreak is spreading under extremely difficult conditions, fuelled by insecurity, displacement, a health workers’ strike and intense population movements.

The WHO has said it remains out of control and is on track to surpass the 2014-2016 West Africa Ebola outbreak, the deadliest on record, which killed more than 11,000 people, primarily in Guinea, Liberia and Sierra Leone.