Recurring outbreaks of infectious diseases have characterized the West African region in the past 4 decades. There is a moderate to high risk of yellow fever in countries in the region, and the disease has reemerged in Nigeria after 21 years. A full-scale simulation exercise of the outbreak of yellow fever was conducted to assess preparedness and response in the event of a full-scale outbreak. The exercise was a multi-agency exercise conducted in Lagos, and it involved health facilities, points of entry, state and national public health emergency operation centers, and laboratories. An evaluation of the exercise assessed the capability of the system to identify, respond to, and recover from the emergency using adapted WHO tools. The majority of participants, observers, and evaluators agreed that the exercise was well-structured and organized. Participants also strongly agreed that the exercise helped them to identify strengths and gaps in their understanding of the emergency response systems and plans. Overall, the exercise identified existing gaps in the current capabilities of several thematic areas involved in a yellow fever response. The evaluation presented an opportunity to assess the response capabilities of multisectoral collaborations in the national public health system. It also demonstrated the usefulness of the exercise in understanding public health officials' roles and responsibilities; enabling knowledge transfer among these individuals and organizations; and identifying specific public health systems-level strengths, weaknesses, and challenges.
Keywords: Ebola virus disease; Evaluation; IDSR technical guidelines; Outbreaks; SIMEX; Simulations; Yellow fever.