Operational insights and lessons learned from coordinating the Nigeria Lassa Epidemiology (NiLE) study in Nigeria

Introduction The CEPI-funded Enable Lassa Research Programme is the largest Lassa fever epidemiological study across seven West African sites to aid vaccine development. In Nigeria, the NiLE study, coordinated by the Enable office at NCDC Abuja, enrolled over 7,000 participants across three sites. This abstract outlines key operational challenges and lessons learned, offering insights to improve future large-scale research in similar low-resource settings. Methods NiLE study was a multi-site, prospective cohort study carried out in Edo, Ondo, and Ebonyi states between 2020 and 2023. Participants were followed for at least 24 months through active and passive surveillance to monitor Lassa fever symptoms, outcomes, and complications. Results Several operational challenges emerged. The COVID-19 pandemic caused significant delays in study initiation and participant enrollment. Mistrust and community hesitancy were heightened due to overlapping health crises, complicating engagement efforts. Effective collaboration with local health authorities proved essential but was not always seamless. Laboratory inconsistencies across sites made case confirmation difficult, while the lack of baseline audiometric data limited the assessment of hearing loss, a known Lassa fever complication. Despite these hurdles, key lessons were identified: the importance of adaptability during public health emergencies, the value of sustained community trust-building, the benefit of integrating local expertise for recruitment and retention, the necessity of standardized lab protocols, and the need for baseline audiometry in Lassa fever studies. Conclusion Coordinating a multi-site study in diverse Nigerian settings presents logistical and cultural challenges. However, with strategic planning, community engagement, and methodological rigor, such initiatives can succeed. The lessons learned from Enable 1.0 provide a framework for improving future research on Lassa fever and other infectious diseases across Nigeria and West Africa