TY - JOUR
T1 - SARS-CoV-2 outbreaks in secondary school settings in the Netherlands during fall 2020; silent circulation
AU - Jonker, Lotte
AU - Linde, Kimberly J.
AU - de Hoog, Marieke L. A.
AU - Sprado, Robin
AU - Huisman, Robin C.
AU - Molenkamp, Richard
AU - Oude Munnink, Bas B.
AU - Dohmen, Wietske
AU - Heederik, Dick J. J.
AU - Eggink, Dirk
AU - Welkers, Matthijs R. A.
AU - Vennema, Harry
AU - Fraaij, Pieter L. A.
AU - Koopmans, Marion P. G.
AU - Wouters, Inge M.
AU - Bruijning-Verhagen, Patricia C. J. L.
N1 - Funding Information: This work was supported in part by ZonMw; Project number 10430022010024. The funder was not involved in the design of the study, collection, analysis and interpretation of data and in writing of the manuscript. Funding Information: Authors gratefully acknowledge the participation of the schools in the study. We further thank our colleagues S. Herfst (Erasmus MC, Rotterdam), M. Tersteeg-Zijderveld, J. Spithoven, A. Timan, I. van Schothorst, S. Parga and P. Meijer (IRAS, Utrecht) for their contribution in environmental sample collection, laboratory preparations and sample processing, and laboratory analysis. This study is funded by ZonMw and part of the Scholen en Covid consortium which also involves D. Zhang, E. Ding, M.A. Ortiz-Sanchez and P.M. Bluyssen (TU Delft, Delft). Saliva analyses were financed in part by the Netherlands Ministry of Health, Welfare and Sport. We also gratefully acknowledge the authors, originating and submitting laboratories of the sequences from GISAID’s EpiFlu Database used in the phylogenetic analysis. All contributors of data may be contacted directly via the GISAID website ( http://platform.gisaid.org ). Publisher Copyright: © 2022, The Author(s).
PY - 2022/12/1
Y1 - 2022/12/1
N2 - Background: In fall 2020 when schools in the Netherlands operated under a limited set of COVID-19 measures, we conducted outbreaks studies in four secondary schools to gain insight in the level of school transmission and the role of SARS-CoV-2 transmission via air and surfaces. Methods: Outbreak studies were performed between 11 November and 15 December 2020 when the wild-type variant of SARS-CoV-2 was dominant. Clusters of SARS-CoV-2 infections within schools were identified through a prospective school surveillance study. All school contacts of cluster cases, irrespective of symptoms, were invited for PCR testing twice within 48 h and 4–7 days later. Combined NTS and saliva samples were collected at each time point along with data on recent exposure and symptoms. Surface and active air samples were collected in the school environment. All samples were PCR-tested and sequenced when possible. Results: Out of 263 sampled school contacts, 24 tested SARS-CoV-2 positive (secondary attack rate 9.1%), of which 62% remained asymptomatic and 42% had a weakly positive test result. Phylogenetic analysis on 12 subjects from 2 schools indicated a cluster of 8 and 2 secondary cases, respectively, but also other distinct strains within outbreaks. Of 51 collected air and 53 surface samples, none were SARS-CoV-2 positive. Conclusion: Our study confirmed within school SARS-CoV-2 transmission and substantial silent circulation, but also multiple introductions in some cases. Absence of air or surface contamination suggests environmental contamination is not widespread during school outbreaks.
AB - Background: In fall 2020 when schools in the Netherlands operated under a limited set of COVID-19 measures, we conducted outbreaks studies in four secondary schools to gain insight in the level of school transmission and the role of SARS-CoV-2 transmission via air and surfaces. Methods: Outbreak studies were performed between 11 November and 15 December 2020 when the wild-type variant of SARS-CoV-2 was dominant. Clusters of SARS-CoV-2 infections within schools were identified through a prospective school surveillance study. All school contacts of cluster cases, irrespective of symptoms, were invited for PCR testing twice within 48 h and 4–7 days later. Combined NTS and saliva samples were collected at each time point along with data on recent exposure and symptoms. Surface and active air samples were collected in the school environment. All samples were PCR-tested and sequenced when possible. Results: Out of 263 sampled school contacts, 24 tested SARS-CoV-2 positive (secondary attack rate 9.1%), of which 62% remained asymptomatic and 42% had a weakly positive test result. Phylogenetic analysis on 12 subjects from 2 schools indicated a cluster of 8 and 2 secondary cases, respectively, but also other distinct strains within outbreaks. Of 51 collected air and 53 surface samples, none were SARS-CoV-2 positive. Conclusion: Our study confirmed within school SARS-CoV-2 transmission and substantial silent circulation, but also multiple introductions in some cases. Absence of air or surface contamination suggests environmental contamination is not widespread during school outbreaks.
KW - Air levels
KW - Outbreak
KW - SARS-CoV-2
KW - Secondary schools
KW - Transmission
UR - http://www.scopus.com/inward/record.url?scp=85144636012&partnerID=8YFLogxK
U2 - https://doi.org/10.1186/s12879-022-07904-3
DO - https://doi.org/10.1186/s12879-022-07904-3
M3 - Article
C2 - 36572861
SN - 1471-2334
VL - 22
JO - BMC Infectious Diseases
JF - BMC Infectious Diseases
IS - 1
M1 - 960
ER -