E3 PreliminaryWeak / uncertainPEM unclearReview-NarrativePeer-reviewedMachine draft
Infection and vaccination in chronic fatigue syndrome: myth or reality?
Appel, Shmuel, Chapman, Joab, Shoenfeld, Yehuda · Autoimmunity · 2007 · DOI
Quick Summary
This review examines whether vaccinations might trigger ME/CFS, since infections can sometimes lead to the condition. The authors found some case reports of ME/CFS occurring after vaccination, but most studies did not find a reliable connection. A Canadian health organization concluded there is no strong evidence linking vaccinations to ME/CFS, though researchers agree more studies are needed.
Why It Matters
This study addresses a significant patient concern about vaccination safety in ME/CFS and clarifies the current state of evidence. Understanding whether and how infections or immune stimulation might trigger ME/CFS could inform both prevention strategies and mechanistic research into the condition.
Observed Findings
- Case reports exist describing ME/CFS occurring after vaccination.
- Prospective and retrospective studies have failed to find consistent association between vaccination and ME/CFS.
- The Canadian Laboratory Center for Disease Control working group found no evidence relating CFS to vaccination.
- Other syndromes (Gulf War syndrome, macrophagic myofasciitis) have been associated with vaccinations in some reports.
Inferred Conclusions
- Current evidence does not support a causal relationship between vaccinations and ME/CFS.
- If infection can trigger an aberrant immune response leading to ME/CFS, the theoretical mechanism exists for vaccination to do so as well.
- Further prospective and retrospective studies are needed to adequately investigate this question.
Remaining Questions
- Could vaccinations trigger ME/CFS in genetically susceptible individuals even if population-level studies show no association?
- What is the temporal relationship between vaccination and ME/CFS symptom onset in reported cases?
- Are certain vaccine types or adjuvants more likely to be associated with ME/CFS onset than others?
What This Study Does Not Prove
This review does not establish that vaccinations cause ME/CFS—it documents the lack of convincing evidence for such a relationship. The existence of case reports does not prove causation, and the absence of large prospective studies means a rare association cannot be completely ruled out. This review also does not definitively explain ME/CFS pathogenesis itself.
Tags
Symptom:Cognitive DysfunctionPainFatigue
Biomarker:Cytokines
Phenotype:Infection-Triggered
Method Flag:PEM Not DefinedWeak Case DefinitionExploratory Only
Metadata
- DOI
- 10.1080/08916930701197273
- PMID
- 17364497
- Review status
- Machine draft
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- Last updated
- 10 April 2026
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 →
Spotted an error in this entry? Report it →