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Long COVID

A patient-coined term for symptoms that persist for weeks or months after the acute phase of SARS-CoV-2 infection has resolved. The clinical names are post-COVID-19 condition (WHO) and post-acute sequelae of SARS-CoV-2, or PASC (NIH).

Edited by M. Callahan · Last reviewed 2026-05-10

How researchers study it

The patient-coined name appeared on social media in spring 2020 and was adopted by clinicians and public-health agencies within a year. The WHO operational case definition, released in October 2021, requires symptoms 3 months from COVID-19 onset, lasting at least 2 months, with no alternative explanation. The NIH RECOVER initiative, launched in 2021, is the largest U.S. effort to define and characterize the condition through prospective cohorts.

A 2023 RECOVER paper proposed a research definition based on 12 symptom clusters scored from a multi-center adult cohort, with post-exertional malaise, fatigue, cognitive dysfunction, dizziness, gastrointestinal symptoms, palpitations, sexual problems, loss of smell/taste, thirst, chronic cough, chest pain, and abnormal movements as the most discriminating features (Thaweethai et al., JAMA, 2023, PubMed 37278994).

Proposed mechanisms under active study include persistent viral reservoirs, autoimmunity, microclots and endothelial injury, reactivation of latent viruses (such as Epstein-Barr), dysautonomia, and mitochondrial dysfunction. No single mechanism has been confirmed to explain all cases; multiple subtypes are likely. The CDC's long-term-effects page tracks the current state of clinical guidance.

Common misconceptions

"Long COVID is one disease."It is currently understood as an umbrella condition with several plausible subtypes and overlapping symptoms. Researchers expect it to eventually be split into distinct entities.
"Long COVID only happens after severe COVID-19."Studies have documented long COVID after mild or even asymptomatic acute infection, though severity does correlate with risk.
"There is a single approved treatment for Long COVID."As of 2026, there is no FDA-approved drug specifically for long COVID. Management is symptom-focused and is being explored through clinical trials, including RECOVER trials in the U.S.
WHAT THIS DOES NOT MEAN This entry defines the condition and names the research definitions. It is not a diagnosis. If you suspect long COVID, working with a clinician who can rule out other causes and refer you to a post-COVID clinic where available is the appropriate path.
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SOURCES
  1. WHO. "Post COVID-19 condition (Long COVID)." who.int
  2. Thaweethai T et al. "Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection." JAMA, 2023. PubMed: 37278994
  3. CDC. "Long COVID or Post-COVID Conditions." cdc.gov
  4. NIH RECOVER initiative. recovercovid.org
Informational only · Not medical advice This entry defines a clinical research term. It does not diagnose, treat, cure, or prevent any disease. For symptoms, consult a licensed clinician — particularly one familiar with post-COVID care.