There is a lack of consensus around the clinical definition of Long COVID which in turn causes challenges with understanding the incidence and prevalence as well as the potential impact for the health care system.
Information about the natural history of Long COVID is incomplete but limited evidence suggests that the immune response trajectories differ for those with few or no symptoms compared to those with severe disease. Individuals with severe disease are more likely to exhibit immunological marker abnormalities but anyone can experience functional limitations.
The mechanisms underlying the development of persistent symptoms in Long COVID remain an enigma. Despite multiple theories, there is little empirical evidence for specific immunological and or biochemical abnormalities in samples of individuals with symptoms consistent with Long COVID.
Risk factors for Long COVID include female gender, older age, higher body mass index, pre-existing asthma and the number of symptoms.
Few studies explored the short-term impact of Long COVID on health care utilization patterns and found a higher impact for those with severe disease compared with mild disease.
Williams-Roberts, H; Groot, G; Reeder, B; Linassi, G; Basran, J; Dalidowicz, M; Mueller, M. Long COVID: What does it mean for the healthcare system and programs to deal with it? 2021 Mar 15; Document no.: EOC021901 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 37 p. (CEST rapid review report)