Recent evidence shows that a range of persistent or new symptoms can manifest after 4-12 weeks in a subset of patients who have recovered from acute SARS-CoV-2 infection, and this condition has been coined long COVID by COVID-19 survivors among social support groups. Long COVID can affect the whole spectrum of people with COVID-19, from those with very mild acute disease to the most severe forms. Like the acute form, long COVID has multisystemic aspects. Patients can manifest with a very heterogeneous multitude of symptoms, including fatigue, post-exertional malaise, dyspnea, cognitive impairment, sleep disturbances, anxiety and depression, muscle pain, brain fog, anosmia/dysgeusia, headache, and limitation of functional capacity, which impact their quality of life. Because of the extreme clinical heterogeneity, and also due to the lack of a shared, specific definition, it is very difficult to know the real prevalence and incidence of this condition. Risk factors for developing long COVID would be female sex, initial severity, and comorbidities. Globally, with the re-emergence of new waves, the population of people infected with SARS-CoV-2 continues to expand rapidly, necessitating a more thorough understanding of potential sequelae of COVID-19. This review summarizes up to date definitions and epidemiological aspects of long COVID.