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

• Main Authors: Can Chen, Changtai Zhu, Danying Yan, Hongchao Liu, Danfeng Li, Yuqing Zhou, Xiaofang Fu, Jie Wu, Cheng Ding, Guo Tian, Lei Lan, Xiaoxiao Liu, Chenyang Huang, Robert Hecht, Lanjuan Li, Shigui Yang
• Format: Article
• Language: English
• Published: Elsevier 2021-03-01
• Series: International Journal of Infectious Diseases
• Subjects: COVID-19; Asymptomatic; Presymptomatic; Covert infections; Epidemiological characteristics; Radiographical findings
• Online Access: http://www.sciencedirect.com/science/article/pii/S1201971221000278

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.