Long COVID: A Modified Delphi Consensus on Definition, Burden, Diagnosis and Management in Southeast Asia

Long COVID is a heterogeneous post-infectious condition following acute severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. Ongoing uncertainty around its definition, burden, diagnosis and management complicates clinical recognition and care in Southeast Asia. A modified Delphi consensus study was conducted with twelve experts from six Southeast Asian countries to develop regional guidance on long COVID. Consensus was predefined as ≥ 80% agreement, corresponding to at least 10 of 12 experts selecting the same response in multiple-choice questions or indicating agreement on Likert-scale questions (e.g. agree/strongly agree, most important/more important, relevant/highly relevant). Questions that reached consensus were removed from the subsequent round, while unresolved questions were revised, consolidated, or expanded. In the final round, a post hoc descriptive category, ‘moderate endorsement’, was applied to Likert-scale questions that had not reached consensus, with ‘important’ as the midpoint category of the five-point importance scale (‘most important’ to ‘least important’), to capture responses judged important but falling short of the consensus threshold. Consensus was reached for all ‘definition’, ‘burden’ and ‘management’ theme questions and most ‘diagnosis’ questions. Experts defined long COVID as unexplained symptoms persisting for > 3 months after SARS-CoV-2 infection, distinct from post-acute COVID-19, with no minimum severity threshold requirement. Long COVID was recognised as affecting approximately 6%–10% of individuals after SARS-CoV-2 infection, consistent with published WHO and KSID estimates; clinical evaluation and symptom-guided testing were recommended for its diagnosis. Hospitalisation during acute COVID-19 was identified as a risk factor for developing long COVID. The experts recommended multidisciplinary, symptom-directed care, rehabilitation, pacing and follow-up. Vaccination and reinfection prevention were supported as important long COVID risk-reduction strategies, and early antiviral treatment should be considered to prevent severe acute illness and hospitalisation in high-risk individuals. Consensus was not reached on the past medical history required for diagnosis; moderate endorsement was observed for booster status, absence of early antiviral treatment, pre-COVID health assessment and standardised patient-reported outcome tools. This Delphi study provides a practical regional consensus framework for long COVID in Southeast Asia.