Epidemiology of COVID-19 infection in young children under five years: A systematic review and meta-analysis

• Published in: Vaccine Vol. 39; no. 4; pp. 667 - 677
• Main Authors: Bhuiyan, Mejbah Uddin, Stiboy, Eunice, Hassan, Md. Zakiul, Chan, Mei, Islam, Md. Saiful, Haider, Najmul, Jaffe, Adam, Homaira, Nusrat
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 22.01.2021; Elsevier Limited
• Subjects: Adult; Age; Asymptomatic Diseases; Child, Preschool; Children; Children younger than five years; Coronaviruses; COVID-19; COVID-19 - epidemiology; COVID-19 - pathology; COVID-19 - transmission; COVID-19 - virology; COVID-19 newborns; Demographics; Demography; Epidemiological Monitoring; Epidemiology; Female; Humans; Incidence; Infant; Infant, Newborn; Infants; Infectious Disease Transmission, Vertical - statistics & numerical data; Intensive Care Units; Literature reviews; Male; Meta-analysis; Mothers; Neonates; Publication Bias - statistics & numerical data; Review; Risk; SARS-CoV-2 - pathogenicity; Severity of Illness Index; Systematic review; Viral diseases; COVID-19; COVID-19 newborns; Children younger than five years
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2020.11.078

Emerging evidence suggests young children are at greater risk of COVID-19 infection than initially predicted. However, a comprehensive understanding of epidemiology of COVID-19 infection in young children under five years, the most at-risk age-group for respiratory infections, remain unclear. We conducted a systematic review and meta-analysis of epidemiological and clinical characteristics of COVID-19 infection in children under five years. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses , we searched several electronic databases (Pubmed, EMBASE, Web of Science, and Scopus) with no language restriction for published epidemiological studies and case-reports reporting laboratory-confirmed COVID-19 infection in children under five years until June 4, 2020. We assessed pooled prevalence for key demographics and clinical characteristics using Freeman-Tukey double arcsine random-effects model for studies except case-reports. We evaluated risk of bias separately for case-reports and other studies. We identified 1,964 articles, of which, 65 articles were eligible for systematic review that represented 1,214 children younger than five years with laboratory-confirmed COVID-19 infection. The pooled estimates showed that 50% young COVID-19 cases were infants (95% CI: 36% − 63%, 27 studies); 53% were male (95% CI: 41% − 65%, 24 studies); 43% were asymptomatic (95% CI: 15% − 73%, 9 studies) and 7% (95% CI: 0% − 30%, 5 studies) had severe disease that required intensive-care-unit admission. Of 139 newborns from COVID-19 infected mothers, five (3.6%) were COVID-19 positive. There was only one death recorded. This systematic review reports the largest number of children younger than five years with COVID-19 infection till date. Our meta-analysis shows nearly half of young COVID-19 cases were asymptomatic and half were infants, highlighting the need for ongoing surveillance to better understand the epidemiology, clinical pattern, and transmission of COVID-19 to develop effective preventive strategies against COVID-19 disease in young paediatric population.