Table 2.

Comparison of currently available definitions of Long COVID or Post-Acute Sequelae of SARS-CoV-2 (PASC).

National Institute of Health (USA) (39)	Centers for Disease Control (USA) (41)	World Health Organization (40)
Wide range and/or constellation of symptoms reflecting lack of recovery “a few weeks” after COVID-19 index infection	Wide range of new, returning, or ongoing symptoms after COVID-19 infection, occurring at least four weeks after COVID-19 infection	Symptoms occurring in an individual with confirmed or suspected COVID-19, usually three months from the onset of COVID-19 infection and lasting at least two months, and which cannot be explained by an alternative diagnosis