Follow-up of long COVID based on the definition of WHO: a multi-centre cross-sectional questionnaire-based study

Since long COVID has hindered people from normal life, it is essential to understand its full spectrum of manifestation. However, it was heterogeneous in the existing studies and few large-scale studies have been conducted on Asian populations. Here, we conducted a multi-centre questionnaire-based study among Chinese people to explore the long COVID based on the definition of WHO.

During March 20, 2023 and June 18, 2023, individuals with a history of confirmed or self-reported SARS-CoV-2 infection were recruited from three hospitals to fill out the questionnaire for long COVID. Each symptom was assigned with 0 to 3 points based on their severity. And the long COVID score was a sum of these points of each symptom. The reporting rate, time trend and risk factors of long COVID stratified by different systems were explored.

3,693 individuals were recruited for the study. The reporting rate of at least one persistent long COVID symptoms and symptoms impacting daily life was 30.2% (1,117) and 10.7% (394). Systemic symptoms (20.7%, 765) were most easily reported. The most common symptoms were fatigue (16.3%, 602), cough (6.3%, 234) and expectoration (5.5%, 203). The reporting rate of long COVID and long COVID score decreased over time during a 180-day follow-up period (P < 0.05). For long COVID, older age (OR: 1.63, 1.38-1.93), female (OR: 1.19, 1.03-1.38) and SARS-CoV-2 reinfection (OR: 3.56, 2.63-4.80) were risk factors; while number of COVID-19 vaccine doses (OR: 0.87, 0.81-0.94) was a protective factor. The use of traditional Chinese medicine (OR: 0.51, 0.37-0.71) was a protective factor for symptoms impacting daily life.

Early interventions should be taken to minimize the impact of long COVID, especially for the elderly, females and those with SARS-CoV-2 reinfection. COVID-19 booster vaccination might play a potential role in minimizing the impact of long COVID.