Ebola Pandemic Risk in 2026: A Low Probability Assessment

Ebola virus disease (EVD), caused by several species of Ebolavirus, presents as a severe, often fatal illness in humans.¹ Transmission occurs through direct contact with the blood, secretions, organs, or other bodily fluids of infected people, and with surfaces and materials contaminated with these fluids.² The incubation period, from infection to the onset of symptoms, typically ranges from 2 to 21 days.³ Initial symptoms are often non-specific, including fever, fatigue, muscle pain, headache, and sore throat, progressing to vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, internal and external bleeding.⁴

Historically, EVD outbreaks have been geographically limited, primarily affecting sub-Saharan Africa.⁵ The largest outbreak occurred in West Africa from 2014 to 2016, resulting in over 11,000 deaths.⁶ This event highlighted critical gaps in global health security, particularly concerning rapid detection, isolation, and contact tracing.⁷ However, the response to this outbreak also spurred significant advancements in vaccine development, therapeutic interventions, and public health preparedness.⁸

Current Preparedness and Risk Assessment

The likelihood of an Ebola pandemic in 2026 is significantly mitigated by several factors that were less developed during previous major outbreaks. Firstly, two EVD vaccines, Ervebo (rVSV-ZEBOV) and Zabdeno/Mvabea (Ad26.ZEBOV/MVA-BN-Filo), have received regulatory approval and demonstrated high efficacy in preventing EVD.^9,10 Ervebo, a single-dose vaccine, has been instrumental in controlling recent outbreaks through ring vaccination strategies, where contacts of confirmed cases and their contacts are vaccinated.¹¹ The availability of these vaccines provides a crucial tool for outbreak containment, reducing the potential for widespread transmission.¹²

Secondly, diagnostic capabilities have improved. Rapid diagnostic tests (RDTs) and polymerase chain reaction (PCR) assays allow for quicker and more accurate identification of EVD cases, facilitating earlier isolation and treatment.¹³ This reduces the window for onward transmission. Surveillance systems, particularly in high-risk regions, have also been strengthened, enabling earlier detection of novel outbreaks.¹⁴

Thirdly, therapeutic options have advanced. Monoclonal antibody treatments, such as Inmazeb (atoltivimab, maftivimab, and odesivimab) and Ebanga (ansuvimab), have shown efficacy in reducing mortality in EVD patients.^15,16 A meta-analysis of four randomised controlled trials demonstrated that these antibody treatments significantly reduced mortality compared to standard care, with a relative risk reduction of approximately 30%.¹⁷ These treatments, when administered early, can improve patient outcomes and potentially reduce viral load, thereby decreasing the risk of transmission.¹⁸

Finally, global and national public health responses have evolved. The World Health Organization (WHO) and national health agencies have developed more robust protocols for outbreak investigation, contact tracing, and community engagement.¹⁹ Lessons learned from the 2014-2016 West African outbreak and subsequent smaller outbreaks have led to better coordination and resource mobilisation.²⁰ While the risk of localised outbreaks remains, the established infrastructure for rapid response, coupled with effective vaccines and treatments, significantly lowers the probability of an uncontrolled, global pandemic by 2026. The primary challenge remains ensuring equitable access to these interventions in resource-limited settings and maintaining vigilance against novel strains or mutations that could evade current countermeasures.²¹