Global Prevalence of Long COVID, Its Subtypes, and Risk Factors: An Updated Systematic Review and Meta-analysis.

Background: This mega-systematic review evaluated the global prevalence of long COVID and its subtypes and symptoms, and assessed the effects of risk factors for long COVID.

Methods: Studies published from 5 July 2021 to 29 May 2024 were searched in PubMed, Embase, and Web of Science, with supplemental updates on 23 July 2024. Data were pooled using a random-effects framework with DerSimonian-Laird estimator. Risk of bias analysis was conducted.

Results: A total of 429 studies were meta-analyzed. The global pooled long COVID prevalence was 36% (95% confidence interval [CI], 33%-40%) with 144 contributing studies. The highest prevalence rates were observed in South America (51% [95% CI, 35%-66%]). The prevalence of long COVID persisted over time, with 35% (95% CI, 31%-39%) at <1 year of follow-up and 46% (95% CI, 37%-57%) at 1-2 years. The most prevalent subtypes were respiratory (20% [95% CI, 14%-28%]) estimated from 31 studies, general fatigue (20% [95% CI, 18%-23%]) from 119 studies, psychological (18% [95% CI, 11%-28%]) from 10 studies, and neurological (16% [95% CI, 8%-30%]) from 23 studies. The 3 strongest risk factors were being unvaccinated for COVID-19 (pooled odds ratio [OR], 2.09 [95% CI, 1.55-2.81]) meta-analyzed from 7 studies, infections from pre-Omicron variants (OR, 1.74 [95% CI, 1.40-2.17]) from 6 studies, and female sex (OR, 1.56 [95% CI, 1.32-1.84]) from 33 studies.

Conclusions: Long COVID is globally prevalent after a severe acute respiratory syndrome coronavirus 2 infection, highlighting a continuing health challenge. The heterogeneity of estimates across populations argues the need for well-designed follow-up studies that use consistent measures and are globally representative.