The Centers for Disease Control and Prevention (CDC) defines long COVID or post-COVID as a disorder that impacts persons previously infected with SARS-CoV-2, the viral cause of COVID-19 as persistent symptoms, or the onset of long-term symptoms, at about or greater than four weeks after acute COVID-19.4
The World Health Organization (WHO) has developed a clinical case definition of post-COVID-19 condition. Post-COVID-19 condition occurs in individuals with a history of probable or confirmed SARS CoV-2 infection, usually 3 months from the onset of COVID-19, with symptoms that last for at least two months and cannot be explained by an alternative diagnosis.5
4. Centers for Disease Control and Prevention, Post-COVID Conditions: Information for Healthcare Providers, April 8, 2021, https://www.cdc.gov/coronavirus.5. World Health Organization: A Clinical Case Definition of post-COVID-19 condition by a Delphi consensus, 6 October 2021, www.WHO.org.