Health outcomes one year after Omicron infection among 12,789 adults: a community-based cross-sectional study.

Summary

In 12,789 adults one year after Omicron infection, long COVID affected 7.8% (persistent 5.1%), with fatigue and post-exertional malaise most common and brain fog rarely resolving. Reinfections substantially increased odds of long COVID (OR 2.59 for one; 6.17 for ≥2). Persistent long COVID was associated with reduced muscle strength, exercise capacity, HRQoL, and higher rates of abnormal lung function.

Key Findings

• Long COVID prevalence at one year was 7.8%, with 5.1% persistent symptoms; fatigue and post-exertional malaise predominated, and brain fog rarely resolved (4.2%).
• Reinfections markedly increased long COVID risk (OR 2.592 for one reinfection; 6.171 for ≥2).
• Persistent long COVID showed lower muscle strength, impaired exercise capacity, worse HRQoL, and higher proportions of abnormal lung function.

Clinical Implications

Prioritize vaccination/boosters and reinfection prevention, screen for persistent deficits with standardized tools, and target rehabilitation for strength, endurance, and respiratory function in long COVID.

Limitations

• Cross-sectional design limits causal inference and temporal dynamics
• Self-reported symptoms and single-region sample may introduce recall or selection biases

Future Directions

Prospective longitudinal cohorts to define trajectories, biomarker-driven endotypes, and randomized rehabilitation trials targeting persistent deficits.