Risk of infection and transmission of SARS-CoV-2 among children and adolescents in households, communities and educational settings: A systematic review and meta-analysis

Abstract

Background There is uncertainty with respect to SARS-CoV-2 transmission in children (0-19 years) with controversy on effectiveness of school-closures in controlling the pandemic. It is of equal importance to evaluate the risk of transmission in children who are often asymptomatic or mildly symptomatic carriers that may incidentally transmit SARS-CoV-2 in different settings. We conducted this review to assess transmission and risks for SARS-CoV-2 in children (by age-groups or grades) in community and educational-settings compared to adults. Methods Data for the review were retrieved from PubMed, EMBASE, Cochrane Library, WHO COVID-19 Database, China National Knowledge Infrastructure (CNKI) Database, WanFang Database, Latin American and Caribbean Health Sciences Literature (LILACS), Google Scholar, and preprints from medRixv and bioRixv) covering a timeline from December 1, 2019 to April 1, 2021. Population-screening, contact-tracing and cohort studies reporting prevalence and transmission of SARS-CoV-2 in children were included. Data were extracted according to PRISMA guidelines. Meta-analyses were performed using Review Manager 5.3. Results Ninety studies were included. Compared to adults, children showed comparable national (risk ratio (RR) = 0.87, 95% confidence interval (CI) = 0.71-1.060 and subnational (RR = 0.81, 95% CI = 0.66-1.01) prevalence in population-screening studies, and lower odds of infection in community/household contact-tracing studies (odds ratio (OR) = 0.62, 95% CI = 0.46-0.84). On disaggregation, adolescents observed comparable risk (OR = 1.22, 95% CI = 0.74-2.04) with adults. In educational-settings, children attending daycare/preschools (OR = 0.53, 95% CI = 0.38-0.72) were observed to be at lower-risk when compared to adults, with odds of infection among primary (OR = 0.85, 95% CI = 0.55-1.31) and high-schoolers (OR = 1.30, 95% CI = 0.71-2.38) comparable to adults. Overall, children and adolescents had lower odds of infection in educational-settings compared to community and household clusters. Conclusions Children (<10 years) showed lower susceptibility to COVID-19 compared to adults, whereas adolescents in communities and high-schoolers had comparable risk. Risks of infection among children in educational-settings was lower than in communities. Evidence from school-based studies demonstrate it is largely safe for children (<10 years) to be at schools, however older children (10-19 years) might facilitate transmission. Despite this evidence, studies focusing on the effectiveness of mitigation measures in educational settings are urgently needed to support both public health and educational policy-making for school reopening.

Demographic characteristics of SARS-CoV-2 B.1.617.2 (Delta) variant infections in Indian population

“…2a). These findings indicate an age shift for delta variant, as the COVID-19 infections with the WT strains were not common in young, and development of severe symptoms and need of hospitalization was primarily limited to adult, more specifically in elderly 17,18 .…”

“…2a). These findings indicate an age shift for delta variant, as the COVID-19 infections with the WT strains were not common in young, and development of severe symptoms and need of hospitalization was primarily limited to adult, more specifically in elderly 17,18 . Furthermore, we observed that, although, proportion of men was still higher than women for contracting infection (59% vs. 41%), a higher proportion of women contracted infection (41% vs. 36%) with delta variant.…”

“…Increased involvement of the lower age groups, primarily young, and narrowing the gap for the rate of infection and severity of illness in terms of age and sex in delta variant infections in comparison to the WT strains, have been indicated by the recent studies and surveillance reports from United Kingdom where there has been a surge in delta variant infections 8,31 . Despite of the established immunological privilege to the young 19,20,32 and women 16 , as were reflected in the infections with WT strains 16,18 , increased risks of contracting infection and severity of illness in these demographic groups, indicates enhanced virulence/lethality in the delta variant.…”

“…The emerging SARS-CoV-2 variants have been reported to vary from wild type (WT) strains (Wuhan strain and B.1) in demographic characteristics, such as age and sex based vulnerability for contracting infection, developing severe illness, and risk of mortality 4,[12][13][14][15] . Against the established pattern of higher vulnerability for the aged and male sex, which is explained by the established immunological reasons [16][17][18][19][20] , the emerging variants are involving young and female sex in increasing proportion 4,[12][13][14][15] . However, the studies, which have examined the shift in demographic characteristics for the delta variant, are currently limited.…”

Sustainable Developmental Goals interrupted: Overcoming challenges to global child and adolescent health

“…This Special Issue has contextual relevance in light of the broad spectrum of direct and collateral effects wrought by the COVID-19 pandemic on social, economic, and health-related conditions [ 6 ]. These effects, direct and indirect, can be grouped broadly in relation to current controversies, such as the upsurge in direct infections among children and adolescents in the wake of the global spread of the B1.617.2 (Delta) variant [ 7 ], and the uncertain relationship of community spread with school closures and reopening [ 8 ]. Currently, the global inequity in COVID-19 vaccine availability and uptake as well as the debate on deferring vaccinations for children and adolescents in high-income countries (HICs) to vaccinate adults in LMICs, also pose major ethical dilemmas [ 9 ].…”