This guideline has been developed jointly by NICE, the Scottish Intercollegiate Guidelines Network (SIGN) and the Royal College of General Practitioners (RCGP).

To develop the recommendations, the following clinical definitions for the initial illness and long COVID were used at different times:

• Acute COVID-19: signs and symptoms of COVID-19 for up to 4 weeks
• Ongoing symptomatic COVID-19: signs and symptoms of COVID-19 from 4 to 12 weeks
• Post-COVID-19 syndrome: signs and symptoms that develop during or after an infection consistent with COVID-19, continue for more than 12 weeks and are not explained by an alternative diagnosis.