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Meta-Analysis
. 2021 Mar:104:458-464.
doi: 10.1016/j.ijid.2021.01.017. Epub 2021 Jan 12.

The epidemiological and radiographical characteristics of asymptomatic infections with the novel coronavirus (COVID-19): A systematic review and meta-analysis

Can Chen  1 , Changtai Zhu  2 , Danying Yan  1 , Hongchao Liu  2 , Danfeng Li  2 , Yuqing Zhou  1 , Xiaofang Fu  1 , Jie Wu  1 , Cheng Ding  1 , Guo Tian  1 , Lei Lan  1 , Xiaoxiao Liu  1 , Chenyang Huang  1 , Robert Hecht  3 , Lanjuan Li  4 , Shigui Yang  5
Affiliations
Meta-Analysis

The epidemiological and radiographical characteristics of asymptomatic infections with the novel coronavirus (COVID-19): A systematic review and meta-analysis

Can Chen et al. Int J Infect Dis. 2021 Mar.

Abstract

Objectives: The role of asymptomatic infections in the transmission of COVID-19 have drawn considerable attention. Here, we performed a meta-analysis to summarize the epidemiological and radiographical characteristics of asymptomatic infections associated with COVID-19.

Methods: Data on the epidemiological and radiographical characteristics of asymptomatic infections were extracted from the existing literature. Pooled proportions with 95% confidence intervals were then calculated using a random effects model.

Results: A total of 104 studies involving 20,152 cases were included. The proportion of asymptomatic individuals among those with COVID-19 was 13.34% (10.86%-16.29%), among which presymptomatic and covert infections accounted for 7.64% (4.02%-14.04%) and 8.44% (5.12%-13.62%), respectively. The proportions of asymptomatic infections among infected children and healthcare workers were 32.24% (23.08%-42.13%) and 36.96% (18.51%-60.21%), respectively. The proportion of asymptomatic infections was significantly higher after 2020/02/29 than before (33.53% vs 10.19%) and in non-Asian regions than in Asia (28.76% vs 11.54%). The median viral shedding duration of asymptomatic infections was 14.14 days (11.25-17.04). A total of 47.62% (31.13%-72.87%) of asymptomatic infections showed lung abnormalities, especially ground-glass opacity (41.11% 19.7%-85.79%).

Conclusions: Asymptomatic infections were more commonly found in infected children and healthcare workers and increased after 2020/02/29 and in non-Asian regions. Chest radiographical imaging could be conducive to the early identification of asymptomatic infections.

Keywords: Asymptomatic; COVID-19; Covert infections; Epidemiological characteristics; Presymptomatic; Radiographical findings.

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Figures

Figure 1
Figure 1
Flow diagram of the study selection process used for this meta-analysis.
Figure 2
Figure 2
Subgroup analysis of asymptomatic individuals among COVID-19 infections. *Statistical differences between subgroups (P < 0.05).
Figure 3
Figure 3
Viral shedding and radiographical findings among asymptomatic and covert infections with COVID-19. (A) The time of viral shedding among the asymptomatic individuals. (B) Radiographical findings among asymptomatic individuals. (C) Radiographical findings among covert infections.
Figure 4
Figure 4
Subgroup analysis of presymptomatic and covert infections among COVID-19 infections. *Statistical differences between subgroups (P < 0.05). (A) Subgroup analysis of presymptomatic individuals among COVID-19 infections. (B) Subgroup analysis of covert infections among COVID-19 infections.
See this image and copyright information in PMC

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