There are currently two approved vaccines against Ebola disease, but neither is approved for use in cases of infection with the Bundibugyo virus.

The Ervebo vaccine (rVSV-ZEBOV) can be used to limit the spread of the disease through a so-called ring vaccination strategy, meaning it is administered to people who have been in contact with an infected individual, secondary contacts, and healthcare workers. Another vaccine can be used both during outbreaks for people at risk of exposure to the virus, and as a preventive measure before outbreaks for frontline responders or those living in areas not yet affected by the outbreak.

However, these two vaccines are currently approved only against the most common virus responsible for Ebola disease (known as the Ebola virus, formerly called the Zaire virus), which notably caused the devastating outbreak in West Africa between 2014 and 2016.

Discussions are underway within the World Health Organization (WHO) to determine which vaccine candidates could be tested in emergency clinical trials against the Bundibugyo virus, as has been done in previous Ebola disease outbreaks. MSF is ready to contribute to this research, as we did during the trials conducted in DRC in 2019. Those trials led to the approval and market release of two vaccines and

It is difficult to make comparisons at this very early stage, but it is indeed concerning that the numbers have already passed previous Bundibugyo outbreaks. Previous Ebola disease outbreaks due to the Bundibugyo virus occurred in 2007 in Uganda (131 cases and 42 deaths) and in DRC in 2012 (Orientale Province – 38 cases, 13 deaths)

An additional major obstacle in the response to this outbreak is the ability to rapidly diagnose those affected by the disease. PCR (Polymerase Chain Reaction) tests require virus-specific diagnostic cartridges. However, these cartridges are currently available in insufficient quantities for the Bundibugyo virus, which considerably slows down case confirmation and, as a result, the implementation of contact tracing and patient isolation.

In the absence of approved treatments and vaccines, the response rests on a combination of epidemiological and public health measures: early isolation of suspected and confirmed cases; daily monitoring of contacts over 21 days with immediate quarantine at the onset of symptoms; strict infection prevention and control protocols (hand hygiene, waste management, chlorinated water points, and personal protective equipment for healthcare workers); safe and dignified burials to prevent transmission during funeral rituals; and on-the-ground epidemiological work to reconstruct transmission chains and identify high-risk practices. It is also critical to ensure continued access to non-Ebola-related care for people in affected areas.

None of this can function without sustained community engagement, informing people and building trust; a far more difficult task in contexts marked by insecurity and limited access to healthcare, such as in the DRC provinces currently affected by the disease.

The urgency of a swift response is underscored by a sobering figure: more than 50 people had already died since the beginning of April, before the outbreak was even officially declared on 15 May — a sign of delayed detection. This is a pattern that is characteristic of the early stages of Ebola disease outbreaks, but especially worrying in the current one in light of the high numbers of suspect cases and deaths already announced.

MSF received the first alerts on 9 and 10 May, reporting a growing number of deaths in the Mongwalu health zone, northwest of Bunia, in Ituri province. Cases were subsequently identified in the Bunia and Rwampara health zones, and a few days later in the neighbouring province of North Kivu, including its capital Goma, pointing to already significant spread across the territory.

Health authorities in Uganda, which shares a border with DRC, confirmed a first case, who died on 14 May. On Sunday, 17 May, the WHO activated its highest alert level in response to the outbreak.

This is the 17th Ebola outbreak DRC has experienced since the first case was discovered in 1976, and the third to specifically involve the Bundibugyo virus, following outbreaks in Uganda in 2007–2008 and in DRC in 2012. Over the past decade, MSF has responded to multiple Ebola disease outbreaks, most notably in West Africa between 2014 and 2016, in DRC between 2018 and 2020, and in Uganda in 2022 and 2025.