Research on post-COVID syndrome: current gaps and future perspectives.

While it is generally assumed that the outcome of an infectious disease is either recovery or death, post-acute infection syndromes have long been documented, representing a substantial healthcare burden with biological drivers remaining poorly understood. Among post-acute infection sequelae, post-COVID syndrome has proved to be an elusive condition with a complex and dynamic presentation. Over the past 3 years, multiple cohorts have been created to understand, prevent, and treat post-COVID-19 condition (PCC). Drawing upon the substantial experience gathered during the pandemic, this viewpoint undertakes a rigorous examination of the methodological challenges inherent in current PCC observational research. By analyzing "real-life" hurdles, we aim to provide clear guidance for future investigations into post-acute infection syndromes and enhance global preparedness for emerging health threats.