SOURCED · CITED · NEVER MEDICAL ADVICE
Home  /  Glossary  /  Post-acute sequelae (PASC)
GLOSSARY · CLINICAL NAMING

Post-acute sequelae of SARS-CoV-2 (PASC)

The U.S. National Institutes of Health's working term for the constellation of symptoms and health consequences that persist or appear after acute SARS-CoV-2 infection has resolved. The same condition is called "post-COVID-19 condition" by the WHO and "long COVID" by patients.

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

How researchers study it

The U.S. NIH announced the RECOVER initiative (Researching COVID to Enhance Recovery) in 2021 with congressional funding to study PASC through prospective adult, pediatric, and pregnancy cohorts; autopsy substudies; electronic-health-record analyses; and clinical trials. RECOVER has enrolled tens of thousands of participants across the U.S. and is the largest single dataset for PASC research.

A 2023 paper from the RECOVER adult cohort proposed a research definition of PASC based on 12 symptom clusters identified by latent class analysis. The most discriminating features were post-exertional malaise, fatigue, cognitive dysfunction, dizziness, gastrointestinal symptoms, palpitations, sexual changes, loss of smell/taste, thirst, chronic cough, chest pain, and abnormal movements (Thaweethai et al., JAMA, 2023, PubMed 37278994).

Multiple proposed mechanisms are under active investigation: viral persistence in tissue reservoirs, autoimmunity, microclots and endothelial injury, reactivation of latent viruses (especially Epstein-Barr), dysautonomia, and mitochondrial dysfunction. RECOVER is running interventional trials of antivirals (extended-course Paxlovid), immunomodulators, and pacing/cognitive rehabilitation. The CDC's long-term-effects page tracks the current state of clinical guidance.

Common misconceptions

"PASC and long COVID are different conditions."They are the same condition under different names. NIH uses PASC for research; WHO uses post-COVID-19 condition; patients and clinicians widely use long COVID.
"PASC is one disease with one mechanism."The current evidence supports multiple subtypes with different underlying mechanisms. Splitting PASC into distinct entities is an active research goal.
"There is an FDA-approved treatment for PASC."As of 2026, no drug is FDA-approved specifically for PASC. Management is symptom-focused; therapeutics are under active trial including in RECOVER.
WHAT THIS DOES NOT MEAN This entry defines the clinical research name and points to research efforts. It is not a diagnosis. PASC evaluation belongs with a clinician who can rule out alternative causes and refer to post-COVID care where available.
RELATED TERMS

Continue across the glossary

RELATED READING

From the journal

SOURCES
  1. NIH RECOVER initiative. recovercovid.org
  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
Informational only · Not medical advice This entry describes a clinical research label. It does not diagnose, treat, cure, or prevent any disease. If you suspect PASC/long COVID, see a licensed clinician.