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

ObjectivesThe 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 with COVID-19.MethodsData on the epidemiological and radiographical characteristics of asymptomatic infections were extracted. Pooled proportions with 95% confidence intervals were calculated using a random effects model.ResultsA 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 the presymptomatic and covert infections were 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%).ConclusionsAsymptomatic infections were more often found in infected children and healthcare workers, and they increased after 2020/02/29 and in non-Asian regions. Chest radiographical imaging could be conducive to early identification of asymptomatic infections.