Characterising long COVID: a living systematic review

Area of Science:

• Medical Research
• Public Health
• Epidemiology

Background:

• Clinical sequelae, known as long COVID, can persist after acute COVID-19 infection.
• The precise nature, frequency, and causes of long COVID remain poorly understood.
• Existing research often has limitations, including high risk of bias and underrepresentation of certain populations.

Purpose of the Study:

• To systematically synthesize current evidence on the characteristics of long COVID.
• To inform clinical management and rehabilitation strategies for long COVID patients.
• To guide future interventional studies aimed at improving long-term health outcomes.

Main Methods:

• A living systematic review methodology was employed.
• Searches were conducted across multiple databases (Medline, CINAHL, Global Health, WHO COVID-19 database, LitCovid, Google Scholar) up to March 17, 2021.
• Included studies involved at least 100 participants with confirmed or suspected COVID-19, assessed at 12 weeks or more post-onset.

Main Results:

• 39 studies (32 cohort, 6 cross-sectional, 1 case-control) involving 10,951 participants were analyzed.
• Commonly reported symptoms include weakness (41%), general malaise (33%), fatigue (31%), concentration impairment (26%), and breathlessness (25%).
• Reduced quality of life was reported by 37% of patients, and 26% of studies indicated reduced pulmonary function.

Conclusions:

• Long COVID is characterized by prolonged, heterogeneous symptoms, making precise definition and risk evaluation challenging.
• There is a critical need for prospective, standardized, and controlled studies.
• Future research should focus on etiology, risk factors, and biomarkers across diverse populations and settings.