NG188, published in December 2020, does not define ‘long COVID’. Instead, it says the term is commonly used to describe signs and symptoms that continue or develop after acute COVID€‘19. It includes both ongoing symptomatic COVID€‘19 and post€‘COVID€‘19 syndrome.”4

These are defined as:

·       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 weeks up 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. It usually presents with clusters of symptoms, often overlapping, which can fluctuate and change over time and can affect any system in the body. Post€‘COVID€‘19 syndrome may be considered before 12 weeks while the possibility of an alternative underlying disease is also being assessed”.

The term ‘syndrome’ was chosen “to reflect the ‘running together’ or concurrence of the multisystem, fluctuating and often overlapping ‘clusters’ of symptoms that people present with.

“The term ‘post’ COVID-19 syndrome was agreed to reflect that the acute phase of the illness has ended, not that the person has recovered.”

The terms ‘chronic’ or ‘persistent’ were not used, in part because there is little long-term evidence indicating how long the ongoing effects seen after a SARS€‘CoV€‘2 infection can last.