DRC begins new vaccine trial as outbreak kills over 4,600

The World Health Organisation (WHO) has announced the commencement of a new Ebola vaccine trial in the Democratic Republic of the Congo (DRC), as health authorities seek to establish whether existing and experimental vaccines can protect against the Bundibugyo strain of the virus.

WHO Director-General, Tedros Ghebreyesus, disclosed this in a statement posted on his official X account on Friday, announcing that the first participants had been vaccinated in Bunia, eastern DRC.

The trial, named Tumaini, which means “hope” in Swahili, will assess vaccine candidates designed to protect against the Bundibugyo virus, for which no vaccine has been approved.

“Science gives us hope,” Mr Ghebreyesus said, describing the trial as a DRC-led effort supported by WHO to establish whether the vaccine candidates could help protect people at risk of infection.

The first vaccination, administered on 23 October, marks the beginning of a Phase II/III clinical trial intended to generate evidence on the safety, immune response and effectiveness of potential vaccines against the virus.

According to the Coalition for Epidemic Preparedness Innovations (CEPI), the trial began as the DRC faced its largest recorded Bundibugyo virus outbreak.

As of 21 October, 9,552 cases and 4,602 deaths had been confirmed in the country, according to information released by the organisations supporting the trial.

Why the trial matters

The Bundibugyo virus belongs to the group of viruses that cause Ebola virus disease. However, it is a different species from the Zaire ebolavirus, against which the existing Ervebo vaccine is licensed.

Although Ervebo is approved for preventing Ebola virus disease caused by the Zaire species, its effectiveness against Bundibugyo virus in humans has not been established.

The Tumaini trial will therefore assess whether Ervebo can provide protection against the strain responsible for the current outbreak.

Two additional vaccine candidates specifically developed against Bundibugyo virus are also expected to enter the study. One is being developed by Moderna, while the other is being developed by the University of Oxford in collaboration with the Serum Institute of India.

The candidates will be assessed for their ability to generate an immune response and protect people against infection. Their inclusion in the trial is expected to help researchers determine which vaccines could offer an effective response to the outbreak.

The study will use an adaptive platform design, allowing multiple vaccine candidates to be evaluated within a single clinical trial framework rather than requiring entirely separate studies.

It will also adopt a ring vaccination approach, which focuses on people who have been in contact with confirmed cases and others at high risk of infection.

The trial is being co-led and co-sponsored by the Institut National de Recherche Biomédicale in the DRC and the University of Antwerp’s Global Health Institute, with the Congolese Ministry of Health providing national leadership and oversight.

WHO is providing technical and scientific advice, while CEPI is supporting the trial through funding and operational expertise.

Previous vaccine efforts

The launch of the Tumaini trial follows earlier efforts by WHO and its partners to determine whether existing Ebola vaccines could protect against the Bundibugyo strain.

PREMIUM TIMES reported in August that WHO had recommended a Phase III clinical trial of Ervebo to establish whether it could protect against the virus, following emerging evidence from laboratory and animal studies suggesting possible cross-protection.

PREMIUM TIMES also reported that the DRC had received an initial allocation of 70,000 doses of Ervebo, with 20,000 intended for a clinical trial and the remaining 50,000 allocated for frontline and health workers.

In August, PREMIUM TIMES also reported that CEPI had committed $4.17 million to research examining whether existing Ebola vaccines could generate immune responses against Bundibugyo virus. The studies involved analysing stored blood samples from people previously vaccinated against the Zaire species.

Separately, PREMIUM TIMES reported in July that a Phase I human trial had begun at the University of Oxford for an experimental vaccine specifically designed against Bundibugyo virus.

The candidate, known as ChAdOx1 BDBV, was developed by the University of Oxford’s Oxford Vaccine Group and Pandemic Sciences Institute in collaboration with the Serum Institute of India and CEPI.

While the earlier Phase I study focuses on assessing the candidate’s safety and immune response in healthy adults, the Tumaini trial is intended to evaluate multiple candidates within the ongoing outbreak response.

A wider public health emergency

The vaccine trial comes amid growing concern over the scale of the outbreak and the absence of an approved vaccine specifically targeting Bundibugyo virus.

The outbreak was declared in the DRC on 15 May and subsequently prompted WHO to declare a Public Health Emergency of International Concern. The Africa Centres for Disease Control and Prevention also declared a Public Health Emergency of Continental Security.

The outbreak has renewed concerns about global investment in vaccine research, particularly for diseases that disproportionately affect African countries.

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PREMIUM TIMES reported on Thursday that Africa CDC Director-General, Jean Kaseya, had criticised the lack of investment in developing a vaccine against Bundibugyo virus, nearly two decades after the strain was first identified in Uganda.

Mr Kaseya argued that the absence of an approved vaccine reflected the failure of the international community to prioritise diseases affecting African populations.

The Tumaini trial is expected to generate evidence that could inform decisions on the use of candidate vaccines during the current outbreak and help strengthen preparedness for future epidemics.

However, the commencement of the study does not mean that a vaccine has already been proven effective against Bundibugyo virus.