Long COVID refers to persistent or new symptoms that continue or appear weeks to months after the initial SARS CoV 2 infection. Research shows it can follow mild, moderate, or severe acute illness, and can even occur after asymptomatic infections.

Common symptoms include fatigue, shortness of breath, chest pain, palpitations, cognitive problems such as difficulty concentrating or “brain fog,” sleep disorders, headache, loss of smell or taste, muscle and joint pain, gastrointestinal issues, and mood changes. Symptoms often fluctuate, with periods of relative improvement and subsequent relapse, sometimes triggered by physical or mental exertion.

Studies indicate that a significant minority of infected individuals develop long COVID, though prevalence estimates vary depending on the criteria used, the variant in circulation, vaccination status, and follow up duration. Vaccination reduces the risk but does not eliminate it. Long COVID appears more frequent in women and in middle age adults, but it can affect all ages, including children.

Proposed mechanisms include lingering viral reservoirs, immune system dysregulation, autoimmunity, microclots and vascular damage, dysautonomia, and persistent inflammation affecting multiple organs, including the brain and heart. Imaging and laboratory studies support involvement of the nervous, cardiovascular, and immune systems, but no single mechanism explains all cases.

There is no specific cure yet. Current management focuses on symptom based care, rehabilitation, pacing to avoid post exertional worsening, and treatment of co existing conditions. Research efforts are ongoing to define diagnostic criteria, understand biological mechanisms, identify risk factors, and test targeted therapies. Long term follow up studies are crucial to determine how often people recover fully, how long symptoms last, and which interventions provide meaningful improvement.