Wessely, S, Chalder, T, Hirsch, S et al. · Lancet (London, England) · 1995 · DOI
This study followed over 2,000 people in the UK to see whether common infections like colds and flu lead to chronic fatigue or ME/CFS. Researchers compared people who had recent infections with those who didn't, and checked them again 6 months later. They found no evidence that routine infections trigger ME/CFS—instead, people who were already tired or stressed before getting sick were more likely to experience fatigue afterward.
This study challenges the common belief that ME/CFS is directly triggered by infections like EBV or COVID-19. For patients and researchers, it suggests that pre-existing fatigue and psychological factors may be more important risk factors than the infection itself, which could redirect clinical attention and research priorities.
This study does not prove that infections never contribute to ME/CFS onset; it only shows that common primary care infections in this population did not predict new chronic fatigue cases. It also cannot rule out that specific infections (severe viral infections, atypical pathogens, or reactivated latent viruses) might play a role in ME/CFS development. The study's focus on relatively mild infections in primary care limits generalizability to severe infections.
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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