What is Long COVID
Key takeaways
Long COVID is symptoms that continue for weeks or months after a COVID-19 infection, recognised in UK guidance under NICE NG188.
It is better thought of as a family of related problems than a single illness, because the picture varies enormously between people.
The severity of the initial infection does not predict who develops it, so mild and even asymptomatic infections can still lead to long COVID.
It is not the same as ME/CFS, but where symptoms map onto ME/CFS, pacing and attention to PEM generally apply.
Long COVID is the patient-coined term for symptoms that continue for weeks or months after a COVID-19 infection. It is recognised in UK clinical guidance under NICE NG188, where the threshold for the longer-term form is twelve weeks.
In medical literature it is sometimes called post-COVID-19 syndrome, or post-acute sequelae of SARS-CoV-2 (PASC). Long COVID is the term most people use, and the one this site defaults to.
It is not one illness
Long COVID is better thought of as a family of related problems than a single illness. For one person it may primarily involve fatigue and post-exertional malaise (PEM). For another, the main issue is breathlessness or heart palpitations. For someone else, cognitive difficulties or persistent gut problems dominate.
This is part of why long COVID is difficult to diagnose and to treat. It is also part of why it is so hard to explain to people who have not experienced it.
How does it start?
Long COVID develops after a COVID-19 infection. That is the one common starting point.
How ill you were at the time predicts very little. Our causes and triggers guide sets out the risk factors research has identified so far.
Symptoms can appear in three broad patterns:
- As a continuation of acute COVID-19 that never fully resolved.
- After a period of apparent recovery, with new symptoms emerging days or weeks later.
- Gradually, with small problems accumulating into something more significant over time.
Who gets it?
Long COVID affects people of all ages and backgrounds. It occurs in people who were previously healthy, in children and teenagers, in older adults, and in those with and without pre-existing conditions.
Research has identified some patterns, including sex, pre-existing conditions, and which symptoms the initial infection involved. These are patterns across populations, not predictors at the individual level, and long COVID affects many people who fit none of them.
Is it the same as ME/CFS?
Not quite, though the two overlap significantly. A substantial proportion of people with long COVID meet the diagnostic criteria for ME/CFS. Where that is the case, ME/CFS management approaches generally apply, particularly pacing and attention to post-exertional malaise.
The main distinguishing features:
- ME/CFS is defined by PEM. Long COVID may or may not involve it.
- ME/CFS can be triggered by many infections, not only COVID-19. Long COVID, by definition, follows a COVID-19 infection.
- Long COVID often involves a wider range of body systems than ME/CFS.
For more on ME/CFS, see our ME/CFS hub.
Related pages
Long COVID symptoms
Fatigue, breathlessness, cognitive difficulties, and the wider symptom picture.
How long COVID is diagnosed
The NG188 framework, and how to prepare for your appointment.
Managing long COVID
Pacing, symptom-specific relief, and working with your GP.
Long COVID causes and triggers
The risk factors, and what makes symptoms worse day to day.