The Blank Page in the Ebola Playbook: The Ebola Bundibugyo Outbreak in the DRC and Uganda

Back in 2014, working as an infection preventionist (IP) at a small community hospital in East Los Angeles, I was planning on how to respond if an Ebola patient walked into our emergency department.

At the time, that felt like a contingency exercise. The West Africa outbreak, the largest in recorded history, had killed more than 11,300 people across Guinea, Sierra Leone, and Liberia. Then Thomas Eric Duncan flew from Liberia to Dallas, walked into a Texas emergency department, and died on October 8, 2014. Two nurses who cared for him contracted Ebola. Suddenly, every IP in the country, from major academic medical centers to small community hospitals with no specialized isolation unit and a laminated emergency manual, was staring at the same question: What do we actually do if this walks through our door?¹

That question is back. And this time, it is harder to answer.

This week, I dug out the Ebola response plan. It had not been touched since 2014. Tucked inside it was a nearly 6-minute donning video we had created and used to train our clinical staff. We ran a mock Ebola patient through to assess what our team could do. Only a few staff members made it through without their masks fogging and successfully drew blood while double-gloved. The verdict: We would make them comfortable before an ambulance took them to a facility better prepared to care for them. In California, that is Cedars-Sinai Medical Center.

If you have been watching the global infectious disease landscape this week, you already know the headlines. The Democratic Republic of the Congo (DRC) has an Ebola outbreak. The World Health Organization (WHO) has declared it a Public Health Emergency of International Concern (Figure 2). There is an infected American.² And unlike every DRC Ebola outbreak in recent memory, and unlike the 2014 outbreak that had us drawing up response plans in community hospital conference rooms across the country, this one is caused by a strain for which the world has no licensed vaccine, no approved treatment, and, if we are being completely honest, almost no operational experience.^3,4

The pathogen is the Bundibugyo ebolavirus. This is only the third time in recorded history that it has caused a documented human outbreak. The first was in Uganda in 2007. The second was in the DRC in 2012. This is the third.^3,5 And it has already progressed to a scale that has alarmed everyone paying attention

For IPs, this may feel far away, but it is moving in real time, and the window between awareness and preparedness is narrowing. We have been here before. We created response plans. When was the last time those plans were updated? When was the last time you tested them?

After 17 Outbreaks, What Makes This One Different?

The DRC has been here before. Sixteen times before, in fact.⁶ Each of those outbreaks was caused by the Zaire ebolavirus. Each one triggered the deployment of Ervebo, Merck's licensed vaccine, which has proven highly effective in ring vaccination campaigns. Each one had access to monoclonal antibody therapies. Finding a successful response plan was hard won, but it saved lives.⁷

This time, we don’t have a vaccine to leverage.

The Bundibugyo strain has a case fatality rate of up to 50%.³ The Ervebo vaccine does not provide coverage. The 2 licensed monoclonal antibody therapies were designed for Zaire and are not indicated here. What is left is supportive care: fluids, electrolytes, and oxygen, where it is available.³

The first known suspected case of this outbreak was a nurse at a health facility who developed symptoms on April 24, 2026, and died 3 days later.^8,9 After the nurse's death, family members handled and prepared the body for burial without protective precautions. The outbreak, already gaining momentum, accelerated. By May 5, the WHO was receiving alerts about an unidentified illness with high mortality spreading across multiple health zones, with 4 more health care workers dead within 4 days of symptom onset.³

What came next will give you pause. All the early field diagnostic tests came back negative. We later learned that this happened because they tested only for the Zaire strain; the Bundibugyo-specific assays simply weren't included in the standard field panel.

It was not until samples were sent to Kinshasa, the capital of the DRC, that the correct viral strain was finally identified on May 14.^2,3 By that point, the virus had a 3-week head start, and the number of suspected cases was already in the hundreds. As of May 19, suspected and confirmed cases have been identified along active trade routes and dense, urban transport hubs on the Rwandan border. The virus has also breached international lines into Uganda’s capital city and, most alarmingly, traveled right back to Kinshasa, a city of 17 million people.^5,6

What About a Vaccine?

Let's talk about the Ervebo vaccine, because you may be asked that question. Ervebo is Merck's licensed recombinant vaccine for Zaire ebolavirus. It works. It has been deployed in DRC outbreak responses since 2018 and is credited with containing multiple outbreaks that would have been far worse without it. However, the vaccine does not provide coverage for this strain.¹⁰

That said, desperate times call for desperate measures. This outbreak could get much bigger if it cannot be contained. And it is worth a conversation.

A WHO technical advisory group convened on May 19 specifically to discuss whether Ervebo might be considered for emergency use anyway.¹⁰ The rationale is narrow but real: Some preclinical animal data suggest that Ervebo may confer partial cross-protective immunity against Bundibugyo.

A spokesperson for Merck, careful in their language, noted that the independent data on non-Zaire strains is limited, has not been generated in humans, and has not come from direct evaluation of Ervebo itself.¹⁰ The WHO's acting lead for the R&D Blueprint group confirmed that any deployment would require a formal request from the governments of DRC and Uganda. There are ethical, evidentiary, and logistical questions that remain unresolved. Expect more updates and possible guidance as the advisory group's recommendations emerge.¹⁰

In parallel, CDC incident managers have confirmed that teams are working to develop a monoclonal antibody therapy specific to Bundibugyo.¹¹ No timeline has been provided. Until something changes, the clinical response is supportive care, and every infection prevention and control measure the facility has. That is the reality on the ground.

What This Means for Your Facility Right Now

Let's be clear about the risk first. As of this writing, the CDC has assessed the overall risk to the American public as low. No cases have been confirmed in the US.⁶ What this outbreak is, however, is a useful mirror. It is a good moment to pull out your high-consequence infectious disease (HCID) policy or special pathogen protocol, blow the dust off it, and ask honestly: When did we last run this? Is the referral pathway to our nearest Regional Emerging Special Pathogen Treatment Center up to date? Does our clinical team know the protocol, or does it live in a binder that nobody has opened since 2015?

On the surveillance side, 2 feeds are worth keeping in your peripheral vision regardless of this specific outbreak. The CDC situation summary is updated regularly with confirmed case counts, geographic spread, and domestic guidance.⁶ WHO's Disease Outbreak Newsis the authoritative international feed.³ Both are free; both are updated in near-real time during an active Public Health Emergency of International Concern (PHEIC), and both take about 3 minutes a day to check. Recommend adding them to your morning routine for the duration of this outbreak.

Finally, consider whether this is a good moment to run a preparedness exercise. Not necessarily an Ebola-specific drill. Just a straightforward HCID tabletop: a febrile patient arrives in your ED with recent travel from an affected region. Walk your team through your protocol. See what still works and what needs updating. Use the heightened awareness around this outbreak to secure organizational buy-in. It’s always better to find gaps on your own terms in a conference room rather than during a real medical emergency.

Additional Resources

Ebola Topics

• CDC. Ebola Disease: Current Situation. https://www.cdc.gov/ebola/situation-summary/index.html
• World Health Organization. Ebola Virus Disease. https://www.who.int/health-topics/ebola#tab=tab_1

Biosurveillance dashboards tracking Ebola

• World Health Organization. WHO Pandemic and Epidemic Intelligence Hub: news monitoring. https://portal.who.int/pandemichub/newsmap/
• Brownstein JS, Freifeld CC, Madoff LC; Boston Children's Hospital. HealthMap: real-time surveillance of emerging infectious diseases. https://www.healthmap.org/en/

References

1. 2014-2016 Ebola outbreak in West Africa. CDC outbreak history. CDC. Reviewed March 8, 2019. Accessed May 19, 2026. https://www.cdc.gov/ebola/outbreaks/index.html
2. Ebola disease outbreak in the Democratic Republic of the Congo and Uganda. CDC. Health Alert Network Advisory No. 530. Published May 17, 2026. Accessed May 19, 2026. https://www.cdc.gov/han/php/notices/han00530.html
3. Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo and Uganda: disease outbreak news, May 15, 2026. World Health Organization. Published May 15, 2026. Accessed May 19, 2026. https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON602
4. CDC mobilizes international response following Ebola disease outbreak in DRC and Uganda. CDC newsroom. Published May 17, 2026. Accessed May 19, 2026. https://www.cdc.gov/media/releases/2026/cdc-mobilizes-international-ebola-response.html
5. Epidemic of Ebola disease caused by Bundibugyo virus in the Democratic Republic of the Congo and Uganda determined a public health emergency of international concern. World Health Organization. Published May 17, 2026. Accessed May 19, 2026. https://www.who.int/news/item/17-05-2026-epidemic-of-ebola-disease-in-the-democratic-republic-of-the-congo-and-uganda-determined-a-public-health-emergency-of-international-concern
6. Ebola disease: current situation. CDC. Updated May 19, 2026. Accessed May 19, 2026. https://www.cdc.gov/ebola/situation-summary/index.html
7. Henao-Restrepo AM, Camacho A, Longini IM, et al. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial. Lancet. 2017;389(10068):505-518. doi:10.1016/S0140-6736(16)32621-6
8. Ministry of Public Health, Hygiene and Social Welfare. Official declaration of the 17th Ebola disease outbreak in the Democratic Republic of the Congo, Ituri Province [cited in WHO DON602]. Published May 15, 2026.
9. Mishra D, Khushi A. Ebola outbreak in DRC and Uganda triggers WHO emergency alert. Zawya. Published May 17, 2026. Accessed May 19, 2026. https://www.zawya.com/en/world/africa/ebola-outbreak-in-drc-and-uganda-triggers-who-emergency-alert-bm7vmdyi
10. Rigby J. International health experts meet in search for Ebola Bundibugyo vaccine options. Zawya. Published May 19, 2026. Accessed May 19, 2026. https://www.zawya.com/en/business/healthcare/international-health-experts-meet-in-search-for-ebola-bundibugyo-vaccine-options-fkyg7n85
11. Transcript: update on Ebola outbreak in the Democratic Republic of the Congo and Uganda. CDC newsroom. Published May 18, 2026. Accessed May 19, 2026. https://www.cdc.gov/media/releases/2026/transcript-update-on-ebola-outbreak-in-the-democratic-republic-of-the-congo-and-uganda-5-18-2026.html