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

Abstract

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.

Keywords: epidemiology; infectious disease; long COVID; postacute sequelae of COVID-19.

Figure 1.

A, Global coverage among the 33 studies included in the meta-analysis by Chen et al [23]. B, Global coverage among the 429 studies included in the current meta-analysis. Countries with >10 studies are marked with circles indicating the exact number of studies. The lack of studies in the gray areas shows the lack of representation in global datasets and the information gap. The change from A to B shows that except for Africa and Oceania, considerable literature has emerged in the past 3 years in other parts of the world.

Figure 2.

Forest plot for pooled long COVID prevalence, corresponding 95% confidence intervals (CIs), and number of contributing studies stratified by hospitalization status, geographical region, follow-up time, biological sex, and age group.

Figure 3.

Forest plot for pooled odds ratio estimates for long COVID associated with 11 risk factors with corresponding 95% confidence intervals and the number of contributing studies. Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; COVID-19, coronavirus disease 2019; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Figure 4.

Examination of heterogeneity by boxplot of overall long COVID prevalence and neurological, psychological, cardiovascular, respiratory, musculoskeletal, dermatological, gastrointestinal, and general fatigue subtype prevalence. Potential sources of true etiological heterogeneity versus study-induced heterogeneity are listed. Abbreviation: COVID-19, coronavirus disease 2019.