Congo-Kinshasa: Ebola Vaccine Trials 'Reason for Hope' in DR Congo and Beyond

Five months after the onset of the Ebola outbreak in the Democratic Republic of Congo, there remains no approved vaccine for the Bundibugyo strain responsible for over 4,000 deaths. However, candidates undergoing trials provide grounds for optimism, according to Emanuele Capobianco of Gavi, the global vaccine alliance. The DRC's deadliest Ebola outbreak has surpassed 9,000 cases, with deaths topping 4,000 by early October.

Among the numerous challenges is the absence of approved vaccines or treatments for the Bundibugyo strain. The first clinical trial of a potential vaccine is slated to commence by the end of October, as per WHO experts.

Ervebo, a vaccine already authorized for the more prevalent Zaire strain of Ebola, will undergo a large-scale human trial in the DRC to assess if it offers any cross-protection against Bundibugyo. Two vaccines specifically targeting Bundibugyo are also under development, one by the University of Oxford and another by the US-based Moderna group.

These are currently in the preliminary stages of testing in smaller-scale clinical trials. Capobianco, director of global health security at Gavi, expressed confidence in their potential to save lives in this and future Ebola outbreaks.

Capobianco informed RFI that there is currently no approved vaccine specifically for the Bundibugyo virus. However, several candidates are under development, offering reasons for hope. Two leading candidates are the one from the University of Oxford and the one from Moderna, which employs messenger RNA (mRNA) technology. Both vaccines target the Bundibugyo virus, relying on different platforms.

The phase 1 trial results, expected in October, will provide insights into their safety and ability to stimulate the immune system. If positive, phase 2 and 3 trials involving larger populations may commence several months later, potentially leading to a rollout in the first half of 2027. Gavi initially mobilized $50 million to support the response, including access to vaccines.

Approximately 70,000 doses of Ervebo were released in August from the global stockpile, funded by Gavi, with a portion utilized for studies. Healthcare workers are also being vaccinated as part of a research protocol to evaluate if Zaire strain protection extends to Bundibugyo.

In the interim, existing Ervebo vaccine could potentially aid in combating the Bundibugyo strain, although its efficacy against it has not been established. Gavi invested ahead of final results to ensure doses are available as soon as their efficacy is proven and authorized for use. The ongoing Ebola outbreak in the DRC is exacerbated by misinformation, which hampers the response.

To encourage vaccination, a vaccine with proven safety and efficacy must be available, and healthcare workers must serve as role models and explain the benefits. Trust-building is crucial, as even with a vaccine available, administration depends on trust. Radio and television, along with direct interaction with respected community figures, can facilitate this process.