The Democratic Republic of Congo (DRC) has launched an Ebola vaccination study targeting frontline health workers in the eastern part of the country, as authorities seek to determine whether an existing Ebola vaccine can provide protection against the Bundibugyo virus responsible for the current outbreak.

Vaccinations began on September 19 in Bunia, the capital of Ituri province and one of the main centers of the Ebola outbreak.

The study, known as BRAVO, is being conducted by Médecins Sans Frontières (MSF) and its epidemiological research center Epicentre, in collaboration with the DRC Ministry of Health, the World Health Organization (WHO), Africa CDC, the Congolese National Institute of Biomedical Research and other scientific partners.

The study will target around 20,000 frontline workers in Ituri and North Kivu provinces. Participants will be followed for nine to 12 months to assess the real-world effectiveness of the Ervebo vaccine against the Bundibugyo virus.

Vaccine was developed for another Ebola strain

Ervebo is the only Ebola vaccine currently available at scale and was developed and licensed to protect against the Zaire strain of Ebola virus.

However, the current outbreak in the DRC is caused by the Bundibugyo virus, for which there is currently no licensed vaccine or proven specific treatment.

Preliminary evidence suggests that Ervebo may provide some level of protection against Bundibugyo virus, but its effectiveness in humans remains uncertain. The BRAVO study is designed to generate scientific evidence on whether the vaccine can reduce infections and severe disease among people at high risk of exposure.

Participation in the study and vaccination are voluntary. Health authorities emphasize that vaccination is an additional protective measure and does not replace infection-prevention measures such as personal protective equipment, safe-care procedures and rapid reporting of symptoms.

70,000 doses made available

The DRC has received approximately 70,000 doses of Ervebo for use during the outbreak. Part of the supply is being used for frontline workers, while the vaccination study will help researchers assess the vaccine's potential effectiveness against the Bundibugyo strain.

WHO has stressed that the effectiveness of Ervebo against Bundibugyo virus has not yet been established in humans. The vaccine is therefore being used within a research framework to generate evidence while the outbreak continues.

Outbreak has spread to seven provinces

The Ebola outbreak in the DRC has become one of the country's most severe Ebola emergencies. By September 2026, more than 7,000 cases and over 3,000 deaths had been reported. The outbreak has spread across seven provinces, while rising transmission in North Kivu remains a particular concern for health authorities.

There have been encouraging signs in Ituri, where transmission has declined, but WHO and other health organizations have warned that it is still too early to declare the outbreak under control.

New vaccines under development

Researchers are also working on vaccine candidates specifically designed to target Bundibugyo virus. In the meantime, Ervebo is being evaluated as an additional protective measure for those most exposed to the virus.

The BRAVO study is not intended to end the outbreak on its own. Its primary objectives are to provide additional protection to high-risk frontline workers and generate scientific evidence on whether Ervebo can protect against the Bundibugyo virus.

Kaynak: Al Jazeera