JMIR Publications

ABSTRACT

Background:

Long COVID induces a substantial global burden of disease.

Objective:

We examined the prevalence of long COVID, its symptom patterns, and its risk factors.

Methods:

We performed a population-based, multi-centre survey by a representative sampling strategy via the Qualtrics platform in Beijing, Shanghai, Guangzhou and Hong Kong (June 2022). We included 2,712 community-dwelling, COVID-19 patients, and measured the prevalence of long COVID symptoms defined by the WHO, and their risk factors. The primary outcomes were the symptoms of long COVID with various levels of impact.

Results:

The response rate was 63.6%. The prevalence of long COVID, moderate or severe long COVID, and severe long COVID was 90.4%, 62.4%, and 31.0%, respectively. Fatigue (33.7%), cough (31.9%), sore throat (31.0%), difficulty in concentration (30.5%), feeling of anxiety (30.2%), myalgia (29.9%), and arthralgia (29.9%) were the most common severe long COVID symptoms. From multivariate regression analysis, female gender (adjusted odds ratio [aOR]=1.49, 95% C.I.=1.13-1.95), engagement in transportation, logistics, or discipline workforce (aOR=2.52, 95% C.I.=1.58-4.03), living with domestic workers (aOR=2.37, 95% C.I.=1.39-4.03), smoking (aOR=1.55, 95% C.I.=1.17-2.05), poor self-perceived health status (aOR 5.06 to 15.38), chronic diseases (aOR 1.92 to 2.71), chronic medication use (aOR=4.38, 95% C.I.=1.66-11.53), and critical severity of COVID-19 (aOR=1.52, 95% C.I.=1.07-2.15) were associated with severe long COVID. Prior vaccination for ≥2 doses of COVID-19 was a protective factor (aOR=0.35-0.22, 95% C.I.=0.08-0.90).

Conclusions:

Long COVID was very common in COVID-19 patients. These findings may inform early identification of COVID-19 patients at risk of long COVID and planning of rehabilitative services. Clinical Trial: The Survey and Behavioural Research Ethics Committee of the Chinese University of Hong Kong approved the study (SBRE-21-0730).