No Vaccine, No Peace: The Bundibugyo Ebola Outbreak Tearing Through Eastern Congo

On May 22, 2026, WHO Director-General Tedros Adhanom Ghebreyesus told reporters that the Ebola outbreak in the Democratic Republic of the Congo was "spreading rapidly" and that "we know the epidemic in the DRC is much larger" than confirmed figures suggest [1]. With nearly 750 suspected cases and 177 suspected deaths across at least 11 health zones, the outbreak has become the third-largest Ebola epidemic in recorded history — behind only the 2014–2016 West Africa crisis (28,616 cases) and the 2018–2020 Kivu outbreak (3,481 cases) [2][3].

But the raw numbers obscure what makes this epidemic distinct and, in several respects, more difficult to contain than its predecessors: the causative agent is Bundibugyo virus, an orthoebolavirus for which no licensed vaccine or therapeutic exists [4]. The outbreak is centered in Ituri Province, one of the most conflict-affected regions on earth, where armed groups have attacked health facilities and displaced 1.7 million people [5]. And the international surveillance architecture that detected and contained previous outbreaks has been significantly weakened by cuts to U.S. foreign aid [6].

Source: WHO

Data as of May 22, 2026CSV

The Virus Without a Vaccine

The Bundibugyo virus was first identified during a 2007 outbreak in western Uganda that infected 149 people and killed 37 [4]. It is one of four orthoebolaviruses known to cause disease in humans, alongside Zaire, Sudan, and Taï Forest strains. Historical case fatality rates for Bundibugyo range from 30% to 50% [7].

The two licensed Ebola vaccines — Merck's rVSV-ZEBOV (Ervebo) and Johnson & Johnson's Zabdeno/Mvabea — target only the Zaire species. Their surface proteins differ enough from Bundibugyo that cross-protection cannot be assumed [4]. Professor Emma Thompson, cited by Gavi, noted that "experimental non-human primate work suggests that rVSV-ZEBOV may provide partial heterologous protection against Bundibugyo virus, but this cannot be assumed to translate into reliable protection in people during an outbreak" [4].

Gavi maintains a global emergency stockpile of approximately 500,000 Ervebo doses, with roughly 2,000 positioned in the DRC [4]. None can be deployed against Bundibugyo without specific WHO authorization and evidence of efficacy that does not yet exist.

Two candidate vaccines targeting Bundibugyo are in development. An rVSV-based candidate could produce clinical trial doses in six to nine months. A ChAdOx-based candidate has a shorter production timeline of two to three months but lacks any animal or human safety data [4]. Neither will be available during the acute phase of this epidemic.

The diagnostic picture adds further complications. The GeneXpert platform — widely deployed across the DRC for rapid pathogen detection — cannot detect Bundibugyo virus, requiring RT-PCR testing instead [8]. This means samples must be transported to reference laboratories, a process that in several documented instances during this outbreak resulted in degraded samples due to shipping delays [6].

How Fast, How Far

The outbreak's acceleration has been steep. The index case — a healthcare worker — developed symptoms on April 24, 2026 [7]. WHO received an alert on May 5. Laboratory confirmation of Bundibugyo virus came on May 14–15, and the DRC Ministry of Health officially declared the country's 17th Ebola outbreak on May 15 [7]. One day later, WHO declared a Public Health Emergency of International Concern (PHEIC) [9].

Source: WHO Situation Reports

Data as of May 22, 2026CSV

As of May 22, 2026, the ACAPS briefing note documented 60 confirmed cases, 105 probable cases, and over 670 suspected cases, with 160 deaths [3]. The Centre for Global Infectious Disease Analysis projected approximately 1,000 potential cases when accounting for undetected transmission [3]. The International Rescue Committee reported that suspected cases surged from 246 to 500 within 96 hours in mid-May — a 103% increase [10].

Geographic spread has been rapid. The outbreak began in Rwampara health zone and has expanded across at least nine health zones in Ituri Province: Bambu, Bunia, Fataki, Logo, Mangala, Mongbwalu, Nizi, Nyankunde, and Rwampara [3]. It has reached North Kivu Province, including the cities of Butembo and Goma, and by May 21, a confirmed case appeared in Miti-Murhesa health zone in South Kivu Province [3].

Most suspected cases are between 20 and 39 years old, with women accounting for over 60% of cases [7] — a demographic pattern consistent with exposure through caregiving and healthcare settings, where women are disproportionately represented.

Two confirmed cases have been reported in Uganda, both in individuals who traveled from DRC. One died in Kampala. As of May 22, no onward transmission from either case had been documented in Uganda [8].

The Conflict Dimension

Ituri Province has been wracked by armed conflict for decades. Multiple armed groups operate in the outbreak zone, and the resulting displacement crisis has left 1.7 million people at crisis-level hunger or worse [5]. Ten million people across Ituri and three other eastern provinces face severe food insecurity driven by conflict [5].

The security environment has directly impeded the Ebola response. WHO described the epicenter as a "highly insecure" area where "ongoing armed conflict" has created displacement that complicates contact tracing [1]. On or around May 22, a security incident resulted in medical tents and supplies being set on fire, which a WHO representative said "significantly jeopardized" response operations [1].

Response teams face restricted movement in active conflict areas. Late case identification, insufficient contact tracing capacity, population mobility, and insecurity constraining case detection are all factors that the ACAPS assessment identified as driving underreporting [3]. The confirmed case count (60 as of May 22) remains far below the suspected total (over 670), in part because testing requires RT-PCR capacity that is difficult to maintain in conflict zones [3][8].

Source: UNHCR Population Data

Data as of Dec 31, 2025CSV

The DRC ranks fourth globally for internally displaced persons, with 5.2 million people displaced — most of them in the eastern provinces now affected by Ebola [11]. This displacement drives exactly the kind of population mobility that accelerates disease transmission across health zones and national borders.

A Surveillance System Under Strain

Multiple former U.S. government officials and aid workers have said that cuts to American foreign assistance contributed to delayed detection of the outbreak [6][12][13].

The numbers are stark. U.S. humanitarian aid to the DRC totaled approximately $1.2 billion in fiscal year 2024. It fell to $715 million in fiscal year 2025. In the first quarter of fiscal year 2026, the U.S. disbursed roughly $67 million [6]. The Trump administration withdrew funding from WHO, dissolved the U.S. Agency for International Development as a standalone agency, made cutbacks at the CDC, and reduced overall health aid to both the DRC and Uganda [12].

Source: USAID/State Department

Data as of May 22, 2026CSV

The operational consequences were specific and measurable. The International Rescue Committee, which had covered five health zones in Ituri with disease surveillance, outbreak preparedness, and WASH infrastructure, scaled back to two zones after U.S. funding ended in March 2025 [10]. Programs that trained healthcare workers and communities to recognize outbreaks were "dismantled or significantly defunded," according to NPR's reporting [6].

Grace Tran, a former USAID Ebola preparedness official, told NPR: "It's more the fact that it circulated for so long, and this thing is much bigger than we've realized. I think that part is related to cuts" [6]. Ana Bodipo-Mbuyamba, a former USAID health director in DRC, said: "When you dismantle those programs, you no longer have your frontline eyes and ears on the ground" [6]. Salim Abdool Karim, who serves on the Africa CDC emergency committee, stated that "the reality is that the US government is missing in action" [6].

The State Department disputed this characterization, saying: "It is false to claim that the USAID reform has negatively impacted our ability to respond to Ebola. In fact, by bringing USAID global health functions under the new GHSD bureau at the State Department, our efforts are more aligned and effective" [12]. The administration mobilized approximately $23 million through UN coordination and announced funding for up to 50 clinics [6].

The International Response

WHO approved $3.9 million from the Contingency Fund for Emergencies, including an additional $3.4 million allocation announced by the Director-General [14]. Within 72 hours of the outbreak declaration, WHO delivered 11.5 tonnes of medical supplies and equipment — personal protective equipment, medical kits, tents, and water, sanitation and hygiene items [15].

The UN peacekeeping mission MONUSCO deployed air assets to establish an "air bridge" transporting WHO emergency supplies from Nairobi to Bunia, the provincial capital of Ituri [15]. The DRC Ministry of Health is coordinating with WHO, UNICEF, the International Organization for Migration, ALIMA, Médecins Sans Frontières, and the DRC Red Cross National Society [15].

Africa CDC declared a Public Health Emergency of Continental Security (PHECS) and convened a high-level meeting with over 130 participants from affected and at-risk countries, donor partners (U.S., UK, EU), UN agencies, pharmaceutical companies, and humanitarian organizations [16].

The IHR Emergency Committee, meeting on May 19 and issuing temporary recommendations on May 22, called for emergency operation centers at national and subnational levels, daily case notification to WHO, enhanced surveillance, decentralized laboratory capacity, and exit screening at all points of entry using questionnaires, temperature checks, and risk assessments [8]. The committee explicitly recommended against flight suspensions and entry denials [8].

Cross-Border Risk

The two confirmed cases in Uganda — both imported from DRC — underscore the cross-border dimension. One case was detected in Kampala, the capital, indicating that infected individuals can travel significant distances before identification [8][7].

WHO assessed the risk to DRC as "very high," to Uganda as "high," and to neighboring border countries collectively as "high" due to "extensive trade, travel, and population mobility throughout the region" [8][1]. The global risk was assessed as "low" [1].

The CDC issued a Level 3 Travel Health Notice for DRC and a Level 1 notice for Uganda [17]. Enhanced airport screening has been implemented, including at Washington-Dulles International Airport in the United States [18]. The European Centre for Disease Prevention and Control published a threat assessment brief characterizing the risk to EU/EEA countries as low but noting the potential for imported cases [19].

Uganda has activated surveillance, screening, and response measures, with support from the CDC for contact tracing, laboratory testing, infection prevention and control, and border health activities [17]. Contact monitoring follows a 21-day protocol after last known exposure [8]. High-risk locations under monitoring include South Kivu, South Sudan, and additional border areas [10].

The Localization Question

The current response has reignited a long-standing debate about the balance between international and local capacity in Ebola response operations. During the 2018–2020 Kivu outbreak, researchers and Congolese civil society organizations argued that hundreds of millions of dollars flowed through international NGOs while local health infrastructure remained chronically underfunded — a pattern that some said created dependency and community distrust [20].

The current response involves a mix of international and Congolese actors. The DRC Ministry of Health leads coordination, with the Congolese national public health institute (INSP) conducting laboratory testing and epidemiological analysis. The DRC Red Cross National Society is engaged in community outreach [15]. But the operational infrastructure — air logistics, supply chains, laboratory equipment, and surge staffing — remains heavily dependent on international organizations and donor funding.

The destruction of medical tents and supplies in a security incident points to another dimension of this problem: community anger. During the Kivu outbreak, Ebola treatment centers were attacked more than 300 times, partly driven by perceptions that the response served international rather than local interests [20]. The current incident, while details remain limited, echoes that pattern.

What Is Driving This Outbreak

Several factors distinguish this epidemic from previous DRC Ebola outbreaks:

The pathogen itself. Bundibugyo virus has caused only two known outbreaks prior to 2026 (Uganda 2007, DRC 2012), meaning clinical and epidemiological knowledge is thinner than for the Zaire species, which has caused at least 15 outbreaks since 1976 [4][7].

No medical countermeasures. Previous DRC outbreaks since 2018 benefited from Ervebo vaccination campaigns using ring vaccination — vaccinating contacts and contacts of contacts. That tool is unavailable here. Supportive care is the only treatment option [4].

Diagnostic gaps. The inability of GeneXpert to detect Bundibugyo, combined with the logistical difficulty of transporting samples to RT-PCR-capable laboratories from conflict zones, means confirmed case counts lag significantly behind actual transmission [8][3].

Urban and peri-urban transmission. The outbreak has reached Bunia (population approximately 700,000) and Goma, one of eastern DRC's largest cities. Urban transmission accelerates spread and complicates contact tracing compared to rural outbreaks [3].

Displacement and mobility. With 5.2 million internally displaced people in the DRC — many concentrated in eastern provinces — population movement creates continuous opportunities for geographic expansion [11][3].

Healthcare worker infections. The index case was a healthcare worker, and the demographic skew toward young women suggests significant nosocomial and caregiving transmission [7].

Degraded surveillance. The reduction in community-based surveillance programs, particularly those previously funded by USAID, meant the outbreak circulated undetected for what experts estimate was weeks to months before the May 15 declaration [6][10].

What Comes Next

The Centre for Global Infectious Disease Analysis projects that the true case count may already approach 1,000 [3]. Without a vaccine, containment depends on classical public health measures — case isolation, contact tracing, safe burial practices, and community engagement — all of which are constrained by active conflict and reduced funding.

The WHO's PHEIC declaration triggers international obligations under the International Health Regulations, including enhanced surveillance at borders and information sharing. But declarations do not automatically generate funding. During the 2018–2020 Kivu outbreak, more than $600 million was spent on the response over two years [20]. The current WHO allocation of $3.9 million and the U.S. commitment of $23 million represent early-stage mobilization that will need to scale substantially if the outbreak's trajectory continues.

The six-to-nine-month timeline for a Bundibugyo-specific vaccine candidate to reach clinical trials means that for the foreseeable future, the DRC and its partners are fighting this outbreak without the tool that proved most effective in containing the Zaire species [4]. Whether the international system can mount an adequate response under these constraints — with a novel-to-most-responders pathogen, in an active war zone, amid reduced funding — is the central question of this epidemic.