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Comprehensive Contact Tracing, Testing and Sequencing Show Limited Transmission of SARS-CoV-2 Between Children in Schools in Norway, August 2020 to May 2021
16 Pages Posted: 8 Nov 2021
More...Abstract
Background: The role of children in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in schools has been a topic of controversy. We investigated transmission from children in comprehensive school contact-investigations and assessed whether these differed by age of the children and by viral variants.
Methods: We prospectively followed school contacts of children with laboratory confirmed SARS-CoV-2 infection in Norway from August 2020 to May 2021. All participants were tested for SARS-CoV-2 twice during the 7–10 days follow-up period, using PCR on home-sampled saliva. Positive samples were whole genome sequenced to determine possible transmission.
Findings: In 43 contact-investigations, 559 child contacts were tested, of which eight tested positive (1·4%, 95% CI 0·62–2·80). We found no significant difference between primary (1·0%, 95% CI 0·27–2·53) and secondary schools (2·6%, 95% CI 0·70–6·39), p=0·229, or between the period before (1·4%, 95% CI 0·50–2·94) and after (1·7%, 95% CI 0·21–5·99) the Alpha variant (B.1.1.7) was established in the study area (March 2021), p=0·665. Only one adult contact (1/100, 1·0%) tested positive. In 34 indexes, we detected 13 different SARS-CoV-2 Pango lineage variants with the B.1.1.7 (Alpha) being the most frequent. In the eight contact-investigations with SARS-CoV-2 positive contacts, four had the same SARS-CoV-2 sequence identity as the index, one had no relation, and three were inconclusive.
Interpretation: We found limited spread of SARS-CoV-2 from children in schools even after rigorous contact tracing and testing of school contacts, including the more transmissible Alpha variant. Whole genome sequencing revealed high consistency in SARS-CoV-2 Pango lineages, but ruled out transmission in one contact-investigation. By excluding contact-investigations with adult cases known at the time of enrollment, our data provide a valid estimate on the role of children in transmission of SARS-CoV-2 in schools.
Funding Information: Norwegian Institute of Public Health.
Declaration of Interests: None of the authors declare competing interests.
Ethics Approval Statement: The Regional Committees for Medical and Health Research Ethics in Norway approved the study (reference 151649). The study complies with the EU general data protection regulation (GDPR) requirements. Consent was obtained from all participants of 16 years or above, or from both parents for participants <16 years. In case of sole parental responsibility, a single consent was sufficient.
Keywords: SARS-CoV-2, COVID-19, child, contact, transmission, secondary attack rate, whole genome sequencing, infection prevention and control, mitigation measures
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