RESUMO
OBJECTIVES: We present the 'COVID-19 evidence ecosystem' (CEOsys) as a German network to inform pandemic management and to support clinical and public health decision-making. We discuss challenges faced when organizing the ecosystem and derive lessons learned for similar networks acting during pandemics or health-related crises. STUDY DESIGN AND SETTING: Bringing together 18 university hospitals and additional institutions, CEOsys key activities included research prioritization, conducting living systematic reviews (LSRs), supporting evidence-based (living) guidelines, knowledge translation (KT), detecting research gaps, and deriving recommendations, backed by technical infrastructure and capacity building. RESULTS: CEOsys rapidly produced 31 high-quality evidence syntheses and supported three living guidelines on COVID-19-related topics, while also developing methodological procedures. Challenges included CEOsys' late initiation in relation to the pandemic outbreak, the delayed prioritization of research questions, the continuously evolving COVID-19-related evidence, and establishing a technical infrastructure. Methodological-clinical tandems, the cooperation with national guideline groups and international collaborations were key for efficiency. CONCLUSION: CEOsys provided a proof-of-concept for a functioning evidence ecosystem at the national level. Lessons learned include that similar networks should, among others, involve methodological and clinical key stakeholders early on, aim for (inter)national collaborations, and systematically evaluate their value. We particularly call for a sustainable network.