WHO Launches First Clinical Trial of Ebola Vaccine in Congo

WHO Director-General Tedros Adhanom Ghebreyesus announced the launch of the first clinical trial of an Ebola vaccine as part of the ongoing disease outbreak in the Democratic Republic of Congo, with initial participants receiving doses of Ervebo vaccine in Bunia, capital of Ituri region in the country's northeast and the epicenter of the outbreak.

Ghebreyesus explained via X platform that Ervebo vaccine, originally approved against the more common Zaire strain, will undergo an expanded trial to determine whether it provides cross-protection against the Bundibugyo strain responsible for the current epidemic, adding: "This trial will help us understand whether any of the candidate vaccines for Bundibugyo virus are effective." He added in a second tweet: "The organization supports this Congo-led effort to find answers and save lives."

Congo announced in May its seventeenth and worst outbreak in history; the total confirmed cases exceeded 9,700 with deaths surpassing 4,600. The organization classified this outbreak as a public health emergency of international concern, the second level on the alert scale. The current outbreak is the most geographically widespread in the continent's history, detected in four countries spanning East, Central, and West Africa.

The trial, known as Tumaini, employs a unified framework that enables testing of safety, efficacy, and immunogenicity of multiple vaccines simultaneously through ring vaccination of patient contacts most vulnerable to infection. Two vaccines specifically designed for the Bundibugyo strain are expected to join the trial 'soon' according to a statement issued by the Coalition for Epidemic Preparedness Innovations (CEPI): the first a ChAdOx1 viral vector vaccine developed by Oxford University, and the second an mRNA vaccine produced by US pharmaceutical group Moderna, with the coalition funding both vaccines.

The trial includes pregnant women and children aged twelve and above, groups often excluded from clinical trials. WHO's emergency director Chikwe Ihekweazu affirmed that the trial was designed to generate the rigorous evidence needed to determine whether participating vaccines are capable of protecting people at risk.