Long COVID & Post-Viral Symptoms
Long COVID (post-COVID condition) is a set of new or ongoing symptoms present 3 or more months after a COVID-19 infection, per CDC and WHO post-COVID condition definitions.
Symptoms
Fatigue is the most common symptom; long COVID is multisystem and often relapsing-remitting, affecting energy, cognition ("brain fog"), the heart and lungs, and the digestive and nervous systems, per large cohort research.
Causes and risk
No single mechanism is established; overlapping hypotheses include lingering viral fragments, immune dysregulation, autoimmunity, reactivation of dormant viruses, microclotting, and autonomic nervous system dysfunction.
How it is evaluated
Evaluation is symptom-guided, ruling out other causes for specific complaints (thyroid dysfunction, anemia, sleep apnea) rather than a single diagnostic test.
Treatment
No curative or FDA-approved therapy exists yet; care focuses on managing individual symptoms, and pacing (rather than graded exercise) is recommended for those with post-exertional malaise, since pushing through can worsen symptoms. Many advertised long COVID treatments (unproven supplements, apheresis, off-label protocols) remain unproven and are best avoided outside of a clinical trial.
When to seek care
New chest pain, severe shortness of breath, or fainting spells should be evaluated urgently to rule out a cardiac or pulmonary complication, which can occur after COVID-19 infection.