Key Points
Question How do updated data from nearly 4000 additional participants and expanded symptom questionnaires inform the prior research classification for long COVID (LC) or post–COVID-19 condition?
Findings In this prospective, observational cohort study, data from 13 647 adults participating in the Researching COVID to Enhance Recovery (RECOVER-Adult) study were used to update the research index for classifying symptomatic LC and 5 symptom subtypes that differ in associated demographic features and quality of life.
Meaning The 2024 LC research index may help researchers identify people with symptomatic LC and its symptom subtypes. Refinement of the index will be needed as research advances and the understanding of LC deepens.
Abstract
Importance Classification of persons with long COVID (LC) or post–COVID-19 condition must encompass the complexity and heterogeneity of the condition. Iterative refinement of the classification index for research is needed to incorporate newly available data as the field rapidly evolves.







