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Meta-Analysis
. 2021 Mar 23;16(3):e0249090.
doi: 10.1371/journal.pone.0249090. eCollection 2021.

Magnitude of asymptomatic COVID-19 cases throughout the course of infection: A systematic review and meta-analysis

Muluneh Alene  1 , Leltework Yismaw  1 , Moges Agazhe Assemie  1 , Daniel Bekele Ketema  1 , Belayneh Mengist  1 , Bekalu Kassie  2 , Tilahun Yemanu Birhan  3
Affiliations
Meta-Analysis

Magnitude of asymptomatic COVID-19 cases throughout the course of infection: A systematic review and meta-analysis

Muluneh Alene et al. PLoS One. .

Abstract

Background: Asymptomatic SARS-CoV-2 infections are responsible for potentially significant transmission of COVID-19. Worldwide, a number of studies were conducted to estimate the magnitude of asymptomatic COVID-19 cases. However, there is a need for more robust and well-designed studies to have a relevant public health intervention. Synthesis of the available studies significantly strengthens the quality of evidences for public health practice. Thus, this systematic review and meta-analysis aimed to determine the overall magnitude of asymptomatic COVID-19 cases throughout the course of infection using available evidences.

Methods: We followed the PRISMA checklist to present this study. Two experienced review authors (MA and DBK) were systematically searched international electronic databases for studies. We performed meta-analysis using R statistical software. The overall weighted proportion of asymptomatic COVID-19 cases throughout the course infection was computed. The pooled estimates with 95% confidence intervals were presented using forest plot. Egger's tests were used to assess publication bias, and primary estimates were pooled using a random effects model. Furthermore, a sensitivity analysis was conducted to assure the robustness of the result.

Results: A total of 28 studies that satisfied the eligibility criteria were included in this systematic review and meta-analysis. Consequently, in the meta-analysis, a total of 6,071 COVID-19 cases were included. The proportion of asymptomatic infections among the included studies ranged from 1.4% to 78.3%. The findings of this meta-analysis showed that the weighted pooled proportion of asymptomatic COVID-19 cases throughout the course of infection was 25% (95%CI: 16-38). The leave-one out result also revealed that the weighted pooled average of asymptomatic SARS-CoV-2 infection was between 28% and 31.4%.

Conclusions: In conclusion, one-fourth of SARS-CoV-2 infections are remained asymptomatic throughout the course infection. Scale-up of testing, which targeting high risk populations is recommended to tackle the pandemic.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Flow chart diagram describing the selection of studies included in the systematic review and meta-analysis on the magnitude of truly asymptomatic SARS-CoV-2 infection, 2020.
Fig 2
Fig 2. Forest plot that shows the weighted pooled proportion of asymptomatic SARS-CoV-2 infection using available studies, 2020.
Fig 3
Fig 3. Funnel plot to check the publication bias of the included studies conducted on truly asymptomatic SARS-CoV-2 infection, 2020.
See this image and copyright information in PMC

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