Post-Viral Fatigue Syndrome

Post-viral fatigue syndrome (PVFS) is a condition characterized by persistent, debilitating fatigue that develops following a viral infection. The fatigue is disproportionate to any ongoing infection and not fully relieved by rest. This condition can follow many viral infections including COVID-19 (often called Long COVID), Epstein-Barr virus (mononucleosis), influenza, and other respiratory viruses. The fatigue may last weeks to months after the initial infection has resolved. PVFS exists on a spectrum - some people recover fully within weeks, while others may develop chronic fatigue syndrome (ME/CFS) if symptoms persist beyond 6 months. The condition appears to involve immune system dysregulation and possibly ongoing inflammation.

Several mechanisms may contribute to post-viral fatigue: 1. Immune System Dysregulation: The immune response may remain activated even after the virus is cleared 2. Mitochondrial Dysfunction: Viral infections can damage mitochondria, the energy-producing parts of cells 3. Autonomic Nervous System Disruption: Affects heart rate, blood pressure, and other automatic functions 4. Inflammatory Cytokines: Persistent elevation of inflammatory markers affects energy levels 5. Viral Persistence: Some viruses may persist in reservoirs even after acute infection resolves 6. Autoimmunity: The immune system may mistakenly attack the body's own tissues Research into Long COVID is rapidly expanding our understanding of these mechanisms.