Evaluation of Post-Acute Sequelae of SARS-CoV-2 (PASC) Index and a Recent Long COVID Criteria in Korean Long COVID-19 Cohort

BACKGROUND: To compare the post-acute sequelae of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (PASC) index and the National Academies of Sciences, Engineering, and Medicine (NASEM) criteria in identifying long coronavirus disease (COVID) among adults with confirmed coronavirus disease 2019. METHODS: A prospective cohort study was conducted from November 2022 to February 2025 at a single tertiary care hospital in Seoul, Korea. Adults aged 18 years or older with confirmed SARS-CoV-2 infection were enrolled, yielding a total of 183 participants. Follow-up assessments took place at 1-, 3-, 6-, and 12-months post-infection. The primary outcome was the prevalence of long COVID at 12 months, measured using the PASC index (≥ 12 points across specified symptoms) and the NASEM criteria (≥ 1 symptom persisting for at least 3 months). RESULTS: Of 183 participants, 26.2% (48/183) met the PASC index, whereas 47.5% (87/183) fulfilled the NASEM criteria. Of the 48 patients who met the PASC index, 44 (91.7%) also met the NASEM criteria. CONCLUSION: The NASEM criteria classified nearly half of participants with long COVID and covered those with PASC index, while the PASC index identified about one quarter. Although the NASEM criteria capture a broader range of persistent symptoms, the PASC index may offer a more stringent threshold, potentially informing targeted research and clinical decision-making.