WHO announces start of Ebola vaccine clinical trial in DR Congo

The World Health Organization has launched the first clinical trial of Ebola vaccines in the Democratic Republic of Congo since the country declared its worst-ever outbreak earlier this year. WHO chief Tedros Adhanom Ghebreyesus said participants had already been vaccinated with the Ervebo shot in Bunia, capital of the northeastern Ituri province and the outbreak's epicentre.

The trial, dubbed Tumaini, will test whether Ervebo — a vaccine already approved against the more common Zaire strain of Ebola — offers any cross-protection against the Bundibugyo species behind the current epidemic. It uses one framework to evaluate the safety, efficacy and immunogenicity of several vaccines, following a ring-vaccination strategy focused on contacts at high risk.

Two Bundibugyo-specific candidate vaccines are also expected to join the trial shortly, according to the Coalition for Epidemic Preparedness Innovations (CEPI). One is a ChAdOx1 adenoviral-vector jab from the University of Oxford; the other, from US-based Moderna, uses mRNA technology.

The study will also enrol pregnant women and children aged 12 and older, generating evidence for populations often excluded from clinical trials. WHO emergencies chief Chikwe Ihekweazu said it aims to produce rigorous evidence that the vaccines protect people at risk.

The DRC declared its 17th Ebola outbreak in May, and has since reported more than 9,700 cases and more than 4,600 deaths. The WHO has declared a public health emergency of international concern, its second-highest alert level, as the outbreak spread to four countries across eastern, central and western Africa — the widest reach of any Ebola outbreak on record.