From pandemics to radiological threats, countries are better prepared when they move from ad-hoc drills to structured programs
In an increasingly unpredictable world, emergencies are no longer rare events, they are recurring tests of national resilience. From pandemics and climate-driven disasters to chemical and radiological and nuclear incidents, countries face a growing spectrum of public health threats.
To support countries prepare more systematically against emergencies, WHO has recently released new global guidance which enables countries to move beyond one-off emergency drills and establish National Health Simulation Exercise Programmes (NHSEP). These are systematic, government-led programs to testing and strengthening preparedness for health emergencies.
Why simulation exercises matter now
Recent global crises continue to show critical weaknesses in coordination, communication, logistics and surge capacity Simulation Exercises offer a safe but realistic environment to identify these gaps before lives are at risk.
As the guidance explains, a national program ensures that exercises are not isolated events but are:
- Based on national risk assessments
- Aligned with health priorities
- Integrated into national monitoring frameworks
- Designed to translate lessons into concrete policy and operational improvements
In short, countries are encouraged to shift from reactive response to continuous readiness.
/health-security-preparedness-(hsp)/country-simulation-exercises-and-reviews-(cer)/ttx-on-radiological-and-nuclear-emergency--ukraine--sept2024.jpg?sfvrsn=8cd3ecc4_1 "TTX on Radiological and Nuclear Emergency, Ukraine, Sept2024"){kind=spacer}
From concept to action: Ukraine’s journey to building an NHSEP
Ukraine demonstrates how the NHSEP concept can move rapidly from guidance to implementation, even in the most challenging operational environments.
The NHSEP concept was first operationally tested during a WHO Simulation Exercise Training of Trainers workshop in Ukraine in August 2024. The training brought together specialists from public health, disaster medicine, emergency services, veterinary medicine, and CBRN preparedness to form a national cadre of facilitators. Following the training, newly trained facilitators were tasked with designing and delivering exercises aligned with national risk priorities and the International Health Regulations.
Building on this foundation, WHO supported a multi-agency tabletop exercise in September 2024 simulating a radiological emergency at a nuclear power plant.
“We aimed to review the ability to respond to radiological-nuclear incidents, test coordination among different actors, improve communication, and identify areas for improvement,” said Dr. Jarno Habicht, WHO Representative in Ukraine
The exercise identified concrete operational gaps that might otherwise have remained undetected, including, ranging from the need for more drills locally to coordination bottlenecks.
These findings provided Ukrainian authorities with an evidence-based roadmap for strengthening radionuclear preparedness, as documented in a paper published in December 2025 in the Disaster Medicine and Public Health Preparedness journal of Cambridge University.
Most importantly, Ukraine did not stop at one exercise. Building on the NHSEP approach, the country has since conducted a series of simulation exercises to continuously test and refine its radionuclear emergency response capabilities.
This is the essence of NHSEP: not a one-time drill, but an evolving national programme of continuous learning.
/health-security-preparedness-(hsp)/country-simulation-exercises-and-reviews-(cer)/ttx-on-radiological-and-nuclear-emergency--ukraine--sept2024_2.jpg?sfvrsn=7e304992_1 "TTX on Radiological and Nuclear Emergency, Ukraine, Sept2024_2"){kind=spacer}
Looking ahead
Health emergencies will continue to grow in complexity. Whether facing pandemics, chemical spills, climate-related disasters or radiological threats, countries cannot afford to rely on ad hoc exercises.
This new WHO guidance provides a tested framework. Ukraine has demonstrated that even during crisis, countries can establish a structured national simulation exercise programme that strengthens coordination, clarifies roles, and improves real-world response.
By institutionalizing simulation exercises through a National Health Simulation Exercise Programme, countries can transform preparedness from a periodic activity into a core pillar of national health security.
HorizonX
WHO is also advancing a global effort through HorizonX, a forward-looking, multi-year simulation exercise programme designed to strengthen preparedness for complex, all-hazard health emergencies through a One Health approach. Through progressively complex exercises conducted in cycles, including tabletop, functional and full-scale simulations, HorizonX provides a dynamic platform to stress-test global and national systems under realistic conditions. Guided by its 4Cs + I framework (Context, Capabilities, Country-centered, Continuity and Impact), the programme ensures that exercises are grounded in real risk environments, measure functional performance rather than static capacity, remain aligned with country priorities, institutionalize continuous learning, and ultimately deliver measurable health security gains at population level.
Together, NHSEP and HorizonX mark a strategic shift, from isolated drills to sustained, system-wide stress-testing of preparedness at national, regional and global levels. By embedding continuous learning and capability assessment into emergency systems, WHO and its partners are helping ensure that when the next crisis strikes, the world responds with tested plans, practiced teams and stronger collective resilience.