International journal of infectious diseases : IJID : official publication of the International Society for Infectious DiseasesJan 11, 2026

Scoring Systems to Measure Long-Term COVID-19 Symptoms in a Korean Group

Long Covid Weekly Brief ↗PubMed ↗DOI ↗

Updated Jan 12, 2026

Abstract

A static scoring system identified 19% of infected participants as positive for persistent symptoms after SARS-CoV-2 infection.

Nine symptoms are strongly linked to persistent symptoms after SARS-CoV-2 infection, with anosmia/ageusia and fatigue being the most significant.
A dynamic scoring system indicated that symptom burdens peaked at 0-5 months post-infection, with a decline observed thereafter.
At the same threshold used in the static score, 33% of infected participants were classified as having persistent symptoms over time.
This study presents a quantitative definition of persistent symptoms after SARS-CoV-2 infection and a framework for ongoing monitoring.

Simplified

OBJECTIVES: Persistent symptoms after SARS-CoV-2 infection (PASC, long COVID) remain a major public-health concern. We developed a data-driven definition and static and dynamic PASC scoring systems in a multicenter, prospective-retrospective observational cohort across 12 South Korean institutions.

METHODS: Adults enrolled December 2022-March 2025 were followed up to 24 months; 8,761 were recruited (7,208 infected; 1,553 controls) and 4,668 met analysis criteria (4,388 infected; 280 controls). Using participant-reported symptoms, surveys, and laboratory data, we identified nine symptoms robustly associated with PASC, with anosmia/ageusia and fatigue most influential.

RESULTS: A static score integrating indicators observed within 24 months yielded an optimal threshold of 13, classifying 19% of infected participants and 4% of controls as PASC positive. A dynamic score tracking six-month intervals showed symptom burdens peaking at 0-5 months post-infection and declining thereafter; at the same threshold, 33% of infected participants were classified as PASC positive, reflecting temporal fluctuation.

CONCLUSIONS: These data establish a quantitative definition of PASC and introduce a dynamic scoring framework to identify and monitor PASC, supporting future clinical research and practice.

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Competing interests

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

PubMed

Scoring Systems to Measure Long-Term COVID-19 Symptoms in a Korean Group

Abstract

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Funding

Competing interests

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