Prevalence, Changes, and Factors Associated with Long COVID in Mainland China after the Policy Shift: Findings from a Two-Wave Cross-Sectional Study

Abstract Background The long-term consequences of the Chinese COVID-19 wave in 2022 remain unknown. Therefore, this study aimed to clarify the long COVID symptoms of COVID-19 survivors after the wave of Omicron in 2022 and to reveal related factors of sequelae symptoms. Methods A repeated cross-sectional survey design was employed, comprising two survey waves conducted in August 2023 and August 2024 among the general population in mainland China. Participants completed an online questionnaire for evaluation of symptoms and characteristics. Univariate and multivariate logistic regression were used to identify factors associated with long COVID. Results A total of 47,464 participants were included. The overall prevalence of long COVID was 52.34%, showing a gradual decline over time, with fatigue being the most prevalent symptom. All estimates were reported as odds ratio (95% confidence interval). Factors positively associated with long COVID included female gender (1.17 [1.12–1.22]), aged 18–59 (1.21 [1.11–1.32]), having any chronic diseases (2.19 [2.07–2.31]) or mental disorders (2.98 [2.85–3.11]) and drinking (1.23 [1.17–1.29]). Conversely, maintaining a regular sleep-wake (0.81 [0.77–0.84]), combining meat and vegetable diets (0.83 [0.78–0.87]), consuming vegetables (0.83 [0.79–0.88]), dairy products (0.91 [0.85–0.98]), and animal foods daily (0.91 [0.86–0.96]), sunbathing at least 5 h per day (0.93 [0.89–0.98]), having a satisfactory neighborhood relationship (0.81 [0.75–0.87]) and community environment (0.71 [0.66–0.75]) and vaccination (2 doses: 0.85 [0.77–0.93]; 3 doses: 0.87 [0.79–0.95]; ≥4 doses: 0.81 [0.70–0.93]) demonstrated significant inverse associations with long COVID. Conclusions Long COVID remains one of the major health challenges and is influenced by a variety of factors. As such, the targeted monitoring, identification, and management of at-risk populations guided by these associated factors carry substantialis public health significance. Community-based programs promoting nutrition and sleep hygiene, combined with sustained vaccination, could help reduce the burden of long COVID. Furthermore, integrating screening and management into routine primary care for high-risk groups, alongside a national surveillance system, represents an actionable policy direction.