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Meta-Analysis
. 2022 Mar;84(3):361-382.
doi: 10.1016/j.jinf.2021.12.026. Epub 2021 Dec 22.

Transmission of SARS-CoV-2 by children and young people in households and schools: A meta-analysis of population-based and contact-tracing studies

Russell Viner  1 , Claire Waddington  2 , Oliver Mytton  2 , Robert Booy  3 , Joana Cruz  4 , Joseph Ward  4 , Shamez Ladhani  5 , Jasmina Panovska-Griffiths  6 , Chris Bonell  7 , G J Melendez-Torres  8
Affiliations
Meta-Analysis

Transmission of SARS-CoV-2 by children and young people in households and schools: A meta-analysis of population-based and contact-tracing studies

Russell Viner et al. J Infect. 2022 Mar.

Abstract

Background: The role of children and young people (CYP) in transmission of SARS-CoV-2 in household and educational settings remains unclear. We undertook a systematic review and meta-analysis of contact-tracing and population-based studies at low risk of bias.

Methods: We searched 4 electronic databases on 28 July 2021 for contact-tracing studies and population-based studies informative about transmission of SARS-CoV-2 from 0 to 19 year olds in household or educational settings. We excluded studies at high risk of bias, including from under-ascertainment of asymptomatic infections. We undertook multilevel random effects meta-analyses of secondary attack rates (SAR: contact-tracing studies) and school infection prevalence, and used meta-regression to examine the impact of community SARS-CoV-2 incidence on school infection prevalence.

Findings: 4529 abstracts were reviewed, resulting in 37 included studies (16 contact-tracing; 19 population studies; 2 mixed studies). The pooled relative transmissibility of CYP compared with adults was 0.92 (0.68, 1.26) in adjusted household studies. The pooled SAR from CYP was lower (p = 0.002) in school studies 0.7% (0.2, 2.7) than household studies (7.6% (3.6, 15.9) . There was no difference in SAR from CYP to child or adult contacts. School population studies showed some evidence of clustering in classes within schools. School infection prevalence was associated with contemporary community 14-day incidence (OR 1.003 (1.001, 1.004), p<0.001).

Interpretation: We found no difference in transmission of SARS-CoV-2 from CYP compared with adults within household settings. SAR were markedly lower in school compared with household settings, suggesting that household transmission is more important than school transmission in this pandemic. School infection prevalence was associated with community infection incidence, supporting hypotheses that school infections broadly reflect community infections. These findings are important for guiding policy decisions on shielding, vaccination school and operations during the pandemic.

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Conflict of interest statement

Declaration of Competing Interests All authors declare no competing interests.

Figures

Fig. 1:
Fig. 1
FLOW diagram.
Fig. 2
Fig. 2
Secondary attack rates from child index cases to all contacts for (A) household studies and (B) school contact-tracing studies.
Fig. 3
Fig. 3
Odds of being a secondary case from child compared with adult index cases.
Fig. 4
Fig. 4
Relative transmissibility of children and adolescents compared with adults in adjusted household models Note: Analysis includes the last two periods from House et al. and estimates by age from other studies.
Fig. 5
Fig. 5
. Prevalence and seroprevalence of SARS-CoV-2 infection in schools by age-group: (A) PCR prevalence and (B) Seroprevalence.
Fig. 5
Fig. 5
. Prevalence and seroprevalence of SARS-CoV-2 infection in schools by age-group: (A) PCR prevalence and (B) Seroprevalence.
Fig. 6
Fig. 6
Plot of predicted prevalence and 95% CI in school studies by community 14-day incidence of SARS-CoV-2 infections per 100,000.
See this image and copyright information in PMC

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