Anticipating Cholera: How Early Action and Modelling Can Save Lives in the DRC

The study by the Swiss Tropical and Public Health Institute, University of Bergen, and UN OCHA shows that early, anticipatory interventions can dramatically reduce cholera cases in the DRC by combining rapid response with vaccination. It highlights that proactive action, supported by system dynamics modelling, is key to shifting from crisis reaction to prevention in global cholera control.

A groundbreaking study by the Swiss Tropical and Public Health Institute, the University of Bergen’s System Dynamics Group, and the Centre for Humanitarian Data at the United Nations Office for the Coordination of Humanitarian Affairs has redefined how outbreaks can be managed in fragile regions. Published in the Bulletin of the World Health Organization in 2025, the research titled “A simulation-based policy analysis of anticipatory action for cholera outbreaks in the Democratic Republic of the Congo” shows that acting early, before an epidemic peaks, can drastically reduce cholera infections and deaths. The study positions anticipatory action as a turning point for disease control, particularly in countries like the Democratic Republic of the Congo (DRC), where cholera remains endemic. Despite being easily preventable and treatable, cholera kills thousands each year, especially in places with unsafe water and poor sanitation. In the DRC, the disease has persisted for decades; between 2008 and 2012, the country accounted for around 14% of global cases. The catastrophic 2017 outbreak, which killed more than 1,100 people, and another resurgence in 2022 underscored how urgently new strategies are needed.

Modelling a Proactive Approach

To investigate how early interventions could reshape epidemic response, the researchers adapted a cholera model originally designed for Yemen and applied it to the DRC’s Nyiragongo health zone in North Kivu province. Using a system dynamics modelling framework, they simulated how cholera spreads and how different responses alter outcomes. The model followed a susceptible–infected–recovered–susceptible (SIRS) structure, showing how people move through stages of vulnerability, illness, recovery, and renewed susceptibility as immunity fades. Transmission was driven mainly by contaminated water, a grim reflection of reality in the DRC, where only about 52% of people have access to safe drinking water and over seven million still practice open defecation.

The model also differentiated between treated and untreated cases. Treated patients, those receiving rehydration therapy in health centres, do not contaminate the environment because their waste is disinfected. Untreated individuals, however, continue shedding Vibrio cholerae into shared water sources, perpetuating the epidemic. When infections in the model reached 15 cases per day, an “anticipatory action trigger” was activated, reflecting the real-life threshold used by the UN to release emergency response funds. At this point, interventions such as water chlorination, hygiene kit distribution, sanitation campaigns, and vaccination drives were rolled out immediately, instead of waiting for a government outbreak declaration.

Four Scenarios, One Message

The study tested four scenarios to compare reactive and proactive responses. The baseline scenario simulated traditional outbreak control measures that begin only after an official declaration, such as treatment, hygiene education, and vaccination. The second scenario introduced anticipatory action, triggering early interventions as soon as the threshold was reached. The third and fourth scenarios combined anticipatory measures with one-dose and two-dose vaccination campaigns, respectively.

The results were striking. In the baseline model, cholera cases rose rapidly and peaked in January 2023, only subsiding temporarily after a mid-January vaccination campaign that covered about 52% of the population. However, as immunity from the single vaccine dose waned after six months, infections rebounded by the end of 2023. In contrast, the anticipatory action scenario showed 24% fewer infections within three months, demonstrating that early action buys valuable time. Yet once these short-term measures stopped, infections resurged, highlighting the importance of sustained efforts. The combination of anticipatory action with early single-dose vaccination reduced infections by 36% within six months, though immunity debt later triggered another wave. The strongest results came from the two-dose vaccination plan, which, despite covering fewer people (26%), provided three years of immunity and prevented a second wave altogether. By early 2024, infections were 9% lower than the baseline, with the lowest cumulative case count overall.

Lessons from the Simulation

The findings reveal that anticipatory action serves as a bridge between emergency response and long-term control. Early interventions curb transmission at the outset, while vaccination consolidates those gains. The study also exposes a key policy dilemma: in low-resource settings, authorities must weigh the benefits of wider one-dose coverage against the durability of two-dose protection. Both strategies can save lives, but the latter offers lasting stability. Moreover, the research stresses that vaccination alone cannot solve the cholera problem. Sustainable water, sanitation, and hygiene (WASH) infrastructure remains indispensable for breaking transmission cycles permanently.

Another crucial contribution of the study is methodological. The use of system dynamics modelling allows policymakers to test and refine outbreak strategies virtually before implementing them in the field. This dynamic tool helps humanitarian agencies allocate limited resources more effectively, simulate possible outcomes, and adapt interventions in real time based on emerging data.

Turning Anticipation into Prevention

Beyond its technical achievements, the research delivers a powerful public health message: the difference between reactive and anticipatory approaches can be measured in lives saved. If early warning systems and funding triggers were embedded into DRC’s national health surveillance protocols, agencies could act weeks earlier, deploying clean water stations, hygiene kits, and vaccination teams before an outbreak spirals out of control. Such a shift would align perfectly with the Global Task Force on Cholera Control’s 2030 Roadmap, which calls for the elimination of cholera as a public health threat.

The study concludes that anticipatory action not only reduces immediate infections but prevents cyclical outbreaks, mitigating what researchers term “immunity debt.” It calls for continuous refinement of the model using real-world data and adaptation for other cholera hotspots across Africa and Asia. By transforming prediction into preparedness and preparedness into prevention, this approach reimagines global epidemic response for the 21st century.