With no approved vaccine for Ebola strain, WHO begins first clinical trial in DR Congo

In a historic move, the World Health Organization has launched its inaugural clinical trial for an Ebola vaccine in the Democratic Republic of Congo.

The World Health Organization (WHO) has announced the launch of the first clinical trial of an Ebola vaccine during the ongoing outbreak in the Democratic Republic of Congo (DRC).WHO director-general Tedros Adhanom Ghebreyesus said on Friday that the first participants had received the Ervebo vaccine in Bunia, the capital of Ituri province in northeastern DRC, which is at the centre of the outbreak.The trial will assess whether Ervebo, which is approved for protection against the Zaire strain of Ebola, can provide any cross-protection against the Bundibugyo virus responsible for the current epidemic, according to news agency AP.“This trial will help us understand whether any of the vaccine candidates designed for Bundibugyo virus work,” Tedros said in a post on X.

DR Congo reports thousands of Ebola cases

The DRC declared its 17th Ebola outbreak in May, which has become the country’s worst on record. Since then, the outbreak has resulted in more than 9,700 reported cases and over 4,600 deaths.In response to the crisis, the WHO declared a public health emergency of international concern, its second-highest level of alert.The outbreak has also been reported in four countries across eastern, central and western Africa, marking the widest geographical spread of an Ebola outbreak on the continent so far.

Multiple vaccine candidates to be assessed

Known as the Tumaini trial, the initiative follows a single clinical trial framework designed to evaluate the safety, effectiveness and immunogenicity of multiple vaccine candidates.The study will adopt a ring vaccination strategy, under which people identified as close contacts of infected individuals and considered at high risk of contracting the virus will be vaccinated.In addition to Ervebo, the trial is expected to include two experimental vaccines specifically developed against the Bundibugyo virus. Both candidates are currently progressing through smaller, early-stage clinical studies.One candidate is an adenoviral vector vaccine, ChAdOx1, being developed by the University of Oxford. The other is an mRNA-based vaccine developed by US biotechnology company Moderna.The coalition for epidemic preparedness innovations (CEPI) has funded both candidates and said they are expected to enter the trial shortly.The study will also include pregnant women and children aged 12 years and above, helping generate evidence for groups that are frequently excluded from clinical research.

WHO stresses need for evidence on vaccine protection

WHO emergencies director Chikwe Ihekweazu said the trial had been designed to produce robust scientific evidence on whether the participating vaccines could protect people at risk of infection.The findings are expected to help researchers determine whether the existing vaccine and the experimental candidates can offer protection against the Bundibugyo strain, for which vaccine options remain limited.The trial represents an important step in efforts to evaluate potential vaccines amid the ongoing Ebola emergency in the DRC and other affected parts of Africa.