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Introduction
Coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus, has
become a global health threat.1 Not only its acute
phase of disease, but so-called “long-COVID” is also a cause of
substantial disease burden.2,3 A systematic review
reported that 80% of patients developed one or more long-term symptoms
and the prevalence of 55 long-term effects of
COVID-19.4
There is no clear definition of long-COVID so far, however, the National
Institute for Health and Care Excellence (NICE) in The UK defined it as
“signs and symptoms that develop during or following an infection
consistent with covid-19 and which continue for more than four weeks and
are not explained by an alternative diagnosis”.5 This
term includes ongoing symptomatic COVID-19, from four to 12 weeks
post-infection, and post-COVID-19 syndrome, beyond 12 weeks
post-infection.6
The symptoms of long-COVID are various and often different from the
acute phase of COVID-19. Miyazato and colleagues reported that the mean
time from COVID-19 symptom onset to the emergence of alopecia was 58.6
days and one of patients presented dysosmia after 92 days after symptom
onset.7 Other symptoms such as general
fatigue,8,9 respiratory
symptoms,10,11 cognitive and mental health
disorder,12,13 and so forth14,15have been reported as long-COVID.
Considering its chronic phase, the disease burden of COVID-19 should be
larger than that of other respiratory infections due to length and
variety of the symptoms. However, the empirical basis for a quantitative
assessment of the disease burden imposed by long-COVID is currently
scant. An important element towards disease burden assessment is
health-related quality of life impact. The objective of the present
study is to collect and analyse empirical information on the
health-related quality of life (HRQoL) due to long-COVID.