Selvakumar, Joel, Havdal, Lise Beier, Brodwall, Elias Myrstad et al. · Brain, behavior, & immunity - health · 2025 · DOI
This study followed young people (ages 12–25) who had COVID-19 to understand why some develop long-lasting fatigue while others recover well. Researchers found that how severe symptoms were in the first few weeks after infection—and psychological factors like loneliness and worry—were much stronger predictors of ongoing fatigue at 6 months than any blood test or physical measure. Surprisingly, whether someone actually had COVID-19 made only a small difference; other life circumstances and emotional stress mattered more.
This study challenges the assumption that persistent post-COVID fatigue is primarily a biological consequence of SARS-CoV-2 infection. Understanding that psychological and social factors are major drivers of fatigue severity could inform prevention and treatment strategies that address mental health, social support, and early symptom management—potentially reducing the burden of long COVID in young people at critical life stages.
This study does not prove that psychological factors *cause* persistent fatigue, only that they are associated with it; the directionality remains unclear. It also does not exclude underlying biological mechanisms in long COVID—absence of biomarker associations does not mean none exist, only that they were not detected in this cohort. Finally, the findings may not generalise to hospitalised patients or older age groups with different trajectories.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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