Background: Asymptomatic infection of SARS-CoV-2 MESHD
may lead to silent community transmission and compromise pandemic control measures of COVID-19 MESHD
. We aimed to estimate the rate of asymptomatic COVID-19 MESHD
infection from published studies, and compare this rate among different patient groups. Methods: The electronic databases including Medline, Embase, PubMed, and three Chinese electronic databases (The Chinese National Knowledge Infrastructure (CNKI), WanFang Data, and VIP HGNC
) were searched. Studies with sample size (or number of subjects) not less than 5 were included. The STATA command ‘Metaprop’ was implemented to conduct meta-analysis for the pooled rate estimates of asymptomatic infections MESHD
with exact binomial and score test-based 95% confidence intervals (CIs). Results: A total of 12,713 COVID-19 MESHD
patients in 136 studies were included in the meta-analysis, including 2,785 asymptomatic infections. The overall rate of asymptomatic infection was 15.1% (95% CI: 12.0%-18.4%). Subgroup analysis showed that the rate was significantly higher in pregnant women (36.3%, 95% CI: 15.7%-59.6%), children (29.4%, 17.4%-42.9%), and studies for screening settings (25.3%, 15.4%-36.5%) conducted on or after 01 March 2020 (27.8%, 15.7%-41.7%). In terms of geographical regions, the rate was the highest in Asia (excluding China) (27.4%, 14.3%-42.6%), followed by Europe (22.7%, 6.3%-44.9%), the US (15.9%, 8.9%-24.3%), and China (13.1%, 10.2%-16.3%). Conclusions: High proportion of asymptomatic infection were observed in pregnant women, children, European residents, screening programmes, and in studies conducted in and after March 2020. Our findings help inform the true burden of COVID-19 MESHD
among different groups of cases, and provide information on cost-effective strategies of identifying and tracing asymptomatic infections.