Race intensifies for Bundibugyo Ebola vaccine as DRC outbreak becomes fastest-spreading on record

Three months into an Ebola outbreak that has already claimed 1,800 lives, the Democratic Republic of the Congo is now home to the second-largest epidemic of the disease ever recorded. What makes this moment different—and urgent—is the speed. More than 4,000 people have been infected in a timeframe that has alarmed global health officials. The World Health Organization declared it a Public Health Emergency of International Concern, and the comparison is stark: the 2014-2016 West African outbreak infected 28,000 people and killed 11,000, but it unfolded over two years. This one is moving at a pace that has no precedent.

The virus in question is the Bundibugyo strain, first identified in Uganda in 2007, and it has never had an approved vaccine. That absence is driving an unusual mobilization. The Coalition for Epidemic Preparedness Innovations, a non-profit based in Oslo, is backing four vaccine candidates through clinical testing. Two have recently entered the first phase of human trials: one developed by Oxford University and the Serum Institute of India, built on technology proven during the Covid-19 response, and another from Moderna using its mRNA platform. A third candidate, modeled on Merck's existing Ebola vaccine for a different strain, is also in the pipeline. Initial results from the first two are expected by late September or early October, with larger trials to follow if those early tests show promise.

Aurélia Nguyen, deputy chief executive of Cepi, frames the approach as deliberate portfolio management. Different vaccine candidates have different strengths and weaknesses, and backing multiple options increases the odds that at least one will work. She notes that the speed itself is remarkable: the time from outbreak to clinical trials has already surpassed the timeline for vaccine development during Covid-19. This outbreak is serving as a live test of something called the 100-day mission, an initiative endorsed by the World Health Organization and the G7 that aims to deliver vaccines, diagnostics, and treatments within 100 days of a new pathogen emerging. Meeting that target this time seems unlikely, but Nguyen argues the trajectory is moving in the right direction. "Every time we have an outbreak, we get better and faster," she says.

But speed in the laboratory is only part of the equation. The epicenter of the outbreak is in northeastern and eastern DRC, a region gripped by active civil conflict. Health authorities and aid organizations have struggled to keep pace with transmission, and the population's trust in health interventions has been eroded by decades of neglect and instability. Cepi is working with organizations like the International Federation of Red Cross and Red Crescent Societies to build community confidence, a process that requires time and cultural sensitivity. When vaccine trials do launch in-country, the work will involve not just explaining the science but engaging local leaders and addressing broader concerns like safe burial practices. The Africa Centres for Disease Control and Prevention and WHO have also raised the possibility that the virus may be mutating, adding another layer of complexity to the response.

Beyond the immediate outbreak, the Ebola crisis is exposing fractures in global pandemic preparedness. A year ago, countries adopted what was hailed as a historic pandemic agreement at the WHO, but negotiations on the specifics—particularly around how governments will share pathogen data and how benefits from resulting vaccines will be distributed—have stalled. Cepi is advising those talks, and Nguyen is candid about the challenge: the private sector has little commercial incentive to develop vaccines for unpredictable epidemic diseases. A binding agreement is necessary to change those incentives, even if the final deal is imperfect.

Funding is another concern. Cepi's own budget, supported by donors including Germany, the United Kingdom, Norway, and the Gates Foundation, has remained relatively stable. The U.S. Congress has even pushed back against attempts to cut the organization's funding. But Nguyen worries about the broader global health sector, which has faced aid cuts. She cites research suggesting the annual cost of pandemic risk going forward exceeds $700 billion. When an outbreak happens, that money must be spent all at once—a reality underscored by the fact that Covid-19 cost $14 trillion in direct economic damage alone. The choice, as she frames it, is whether to invest in preparedness now or pay far more later in response.

For the people in the DRC, the stakes are immediate and devastating. The outbreak is unfolding in a population already battered by conflict and health crises. Even if a vaccine is ready within weeks, the work of reaching people, building trust, and stopping transmission will take far longer. The race against the clock is real, but so is the race against mistrust, geography, and the simple fact that viruses do not wait for diplomacy or funding cycles to align.