E3 PreliminaryModerate confidencePEM unclearReview-NarrativePeer-reviewedMachine draft
Hemostatic Disorders Following Severe Acute Respiratory Syndrome Coronavirus 2 Infection, COVID-19 Vaccination, and Long-COVID Syndrome: Current Evidence and Controversies in Clinical Practice.
Vishnu, Prakash, Aboulafia, David M · Clinics in laboratory medicine · 2025 · DOI
Quick Summary
This review examines blood clotting problems that have been reported in people with COVID-19, those who received COVID-19 vaccines, and people with Long-COVID (including ME/CFS-like symptoms). The authors summarize what we know about these clotting issues, ranging from minor platelet problems to serious blood clots, and discuss areas where doctors and researchers disagree about what's happening and why.
Why It Matters
Many ME/CFS patients report having or suspecting hemostatic (blood clotting) abnormalities, and some ME/CFS cases emerge or worsen after COVID-19 infection or vaccination. This comprehensive review of clotting complications helps clarify what is currently known and where evidence gaps exist, potentially informing clinical investigation and management of hemostasis in Long-COVID and ME/CFS populations.
Observed Findings
- Hemostatic disorders ranging from mild platelet dysfunction to severe thromboembolic events have been documented following SARS-CoV-2 infection.
- Vaccine-induced immune thrombotic thrombocytopenia (VITT) has emerged as a rare but serious coagulation-related adverse effect following COVID-19 vaccination.
- A substantial proportion of individuals develop persistent Long-COVID symptoms including fatigue, brain fog, and post-exertional malaise after acute SARS-CoV-2 infection.
- Hemostatic complications are recognized as a significant concern in both acute COVID-19 and the post-acute phase.
Inferred Conclusions
- Hemostatic disorders represent an important clinical complication across the spectrum of SARS-CoV-2-related illness, from acute infection through Long-COVID.
- Significant controversies and evidence gaps remain regarding the mechanisms, prevalence, and clinical significance of hemostatic abnormalities in these conditions.
- Current evidence is insufficient to fully clarify the relationship between hemostatic complications and persistent Long-COVID symptoms.
Remaining Questions
- What is the true prevalence and incidence of hemostatic abnormalities in Long-COVID and ME/CFS populations?
- Do specific hemostatic defects directly contribute to post-exertional malaise, fatigue, or cognitive dysfunction, or are they epiphenomena?
What This Study Does Not Prove
As an evidence map and review article, this study does not prove causation between COVID-19 or vaccination and specific hemostatic disorders in any individual patient—it summarizes existing evidence and acknowledges controversies rather than establishing definitive causal mechanisms. The abstract does not clarify whether hemostatic abnormalities are directly responsible for Long-COVID symptoms like fatigue and post-exertional malaise, nor does it establish prevalence or incidence rates across populations.
Tags
Symptom:Post-Exertional MalaiseCognitive DysfunctionFatigue
Biomarker:Blood Biomarker
Phenotype:Infection-TriggeredLong COVID Overlap
Method Flag:PEM Not Defined
Metadata
- DOI
- 10.1016/j.cll.2025.07.008
- PMID
- 41161981
- Review status
- Machine draft
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- Last updated
- 8 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 →
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