A growing Ebola outbreak in the Democratic Republic of Congo (DRC) has already spread to Uganda and carries a nearly 70 per cent probability of reaching South Sudan within weeks, according to a new modelling study published in The Lancet Infectious Diseases.
As of June 22, 2026, the outbreak caused by the Bundibugyo strain of the Ebola virus had resulted in 1,048 laboratory-confirmed cases and 267 deaths in DRC. The virus circulated undetected for nearly six weeks before being identified by the World Health Organisation (WHO).
In the absence of an approved vaccine against the Bundibugyo strain, researchers from the WHO Regional Office for Africa have urged neighbouring countries to immediately strengthen public health measures, including border surveillance, contact tracing and safe burial practices. While DRC’s intensified response efforts are beginning to show signs of slowing transmission, the outbreak remains a significant regional threat.
Using computer-based transmission models, researchers simulated the outbreak under low, medium and high transmission scenarios. Under the most likely scenario, cumulative confirmed cases were projected to reach around 990 by late June 2026, with approximately 174 deaths, before rising sharply to an estimated 8,210 cases by September 2026 if transmission continues.
How neighbouring countries may be affected
Dr Marie Rosaline Belizaire, WHO’s Emergencies Director for Africa and incident manager for the outbreak, who is also among the study authors, said South Sudan represents the most urgent preparedness priority. The study estimates a 69.3 per cent probability that at least one Ebola case will be imported into South Sudan within the 12-week modelling period.
“South Sudan also has some of the weakest public health infrastructure in the region, with known gaps in case management, contact tracing, safe burial practices and border surveillance,” the researchers noted.
Rwanda, with an estimated importation risk of 8.6 per cent, and Burundi, at 2 per cent, currently face substantially lower risks. However, the authors cautioned that these estimates could change depending on surveillance capacity, travel patterns and the speed of response in each country.
The researchers emphasised that the projections are intended as an early situational assessment to guide preparedness efforts rather than precise forecasts and will be updated as more verified data become available.
COVID lessons shape Ebola response
As health authorities work to contain the outbreak, global efforts are under way to accelerate vaccine development.
Dr Richard Hatchett, Chief Executive Officer of the Coalition for Epidemic Preparedness Innovations (CEPI), announced that the organisation has committed up to $100 million from existing resources to support the development of vaccines against the Bundibugyo Ebola virus circulating in DRC and Uganda.
Speaking during a virtual media briefing organised by Harvard TH Chan School of Public Health, Dr Hatchett said the outbreak underscored a broader lesson from recent global health crises. “It is not a question of if, but when pandemics occur. We do not know the timing, but we can be certain that more will come. This is not a situation where we can afford a wait-and-see approach. It calls for an all-hands-on-deck response, bringing substantial resources and treating it like a fire that requires immediate containment rather than passive monitoring,” he said.
No vaccine remains the biggest challenge
According to Dr Hatchett, the most significant challenge is the absence of a licensed vaccine for the Bundibugyo strain. He warned that the situation bears similarities to the 2014 West Africa Ebola outbreak, when delayed international action allowed the epidemic to escalate dramatically.
“The lesson from that experience is clear: scale up the response early, before the situation becomes unmanageable. This is a rapidly growing, potentially exponential process. By the time the growth becomes obvious, it can accelerate very quickly. The priority must be to strengthen control measures now before the outbreak spirals further,” he warned.
India’s vaccine advantage
Dr Hatchett highlighted India’s vaccine manufacturing capacity as a critical global asset. “India’s COVID-19 response demonstrated its ability to rapidly scale vaccine production, with institutions such as the Serum Institute of India (SII) showing remarkable manufacturing capability and partnership capacity,” he said.
He noted that influenza viruses and coronaviruses continue to pose the greatest pandemic threat to South Asia because of their ability to spread efficiently through large populations. “Nipah virus is also a significant concern for India because of its presence in the region, although it currently lacks the level of transmissibility required to trigger a large-scale pandemic,” he said. “However, any evolution that increases its transmissibility could dramatically raise its threat level.”
Dr Hatchett identified three key areas for India’s pandemic preparedness. First, India should expand surge manufacturing capacity to ensure it can rapidly vaccinate its own population while continuing to serve as a major global supplier during health emergencies. Second, it should strengthen technology-transfer partnerships with countries across the global South, particularly in Africa, to build regional resilience against future outbreaks. Third, India should champion greater regulatory coordination across South and Southeast Asia so that vaccines, diagnostics and treatments can be approved and deployed simultaneously during public health emergencies.
“These investments would not only improve India’s preparedness during the first 100 days of the next pandemic but also reinforce its position as a global leader in epidemic response,” Dr Hatchett said.
The study estimates a 69.3 per cent probability that at least one Ebola case will be imported into South Sudan within the 12-week modelling period. (Source: File) 
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