COVID-19 in B.C.: Vancouver Coastal Health cites research papers to back claim that HEPA filters not needed in schools

The Safe Schools Coalition B.C. feels that these devices will reduce the risk of transmission for students, staff, and teachers—and one study supports this viewpoint

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      The Ontario government has installed stand-alone high-efficiency particulate air filters, a.k.a. HEPA filters, in all learning environments in the K-12 system.

      The Safe Schools Coalition B.C. also wants this done in B.C., which was covered earlier this month in a Straight cover story. That's because the coalition feels that these devices will reduce the likelihood of airborne COVID-19 transmission.

      However, B.C. health authorities and the NDP provincial government have refused to do this.

      Vancouver Coastal Health justified this decision in a post on its website. This has come even though a study (reported deeper in this article) shows that HEPA filters can sharply decrease the concentration of the virus in a classroom with an infected person.

      The health authority still insists that HEPA filters are not necessary because "there is no evidence that ventilation systems, in good operating condition, are contributing significantly to the spread of the virus in BC schools".

      "Like most common respiratory viruses, COVID-19 spreads primarily through respiratory droplet transmission within a short range," Vancouver Coastal Health declares. "Most commonly, students and staff who test positive for COVID-19 acquire the virus through close contact with a case at home or through their social networks.

      "Unfortunately, school-based ventilation changes are unlikely to prevent transmissions in homes and social networks," the statement continues. "In-school transmission accounts for approximately 1% of COVID-19 cases."

      This statement was updated on January 10, less than a week after the Straight's cover story appeared.

      Vancouver Coastal Health updated this statement on January 10.

      Unpublished study contradicts health authority's position

      A preprint paper on the medRxiv website has come to a radically different conclusion than B.C. public-health officials and the Ministry of Health and Ministry of Education.

      This paper, which has not yet undergone peer review, evaluated the effectiveness of different interventions against aerosol transmission of COVID-19.

      The researchers determined that one HEPA filter was as effective as two school windows being kept partly open all day during winter. In fact, a single HEPA filter led to a 2.5-fold decrease in the concentration of virus particles in a classroom of 160 square metres with one infectious individual, according to the study.

      Furthermore, it found that two HEPA filters led to a four-fold decrease in the concentration of virus particles.

      "Combined interventions (i.e., natural ventilation, masks, and HEPA filtration) were the most effective (≥ 30-fold decrease). Combined interventions remained highly effective in the presence of a super-spreader," the paper concluded.

      The lead author is Jennifer Villers, a molecular biologist, epidemiologist, and disease modeller at the University of Geneva.

      She and her fellow researchers relied on the CERN-developed COVID Airborne Risk Assessment Tool. (More information on CERN is available here.)

      Health authority calls COVID-19 a "respiratory virus"

      Vancouver Coastal Health describes COVID-19 as a "respiratory virus" even though some health experts have said that it's much more than a respiratory virus and should not be framed that way.

      "If you frame it as a respiratory virus, you have permission to call it mild, to say it’s nothing but sniffles for kids. And that’s commonly out there and I’ve heard that articulated in B.C. and elsewhere," University of Toronto public-health researcher Colin Furness said in a recent talk hosted by Protect Our Province B.C. It's a group of health-care workers and researchers trying to raise awareness about the airborne nature of COVID-19.

      "But here’s the thing: COVID, before we even get to Omicron, COVID is not a respiratory disease," he continued. "It’s a vascular disease that has an initial respiratory phase in kids and increasingly in adults. The respiratory phase is less dangerous, less acute. It looks like sniffles.

      "The problem is not the sniffles. The problem is what the virus is doing elsewhere in the body from the toes to the testes to the brain. It is causing autoimmune disease. It is causing loss of brain tissue."

      In his words, the disease has led to "brain tissue disappearing" in adults.

      "And autopsies of bodies have shown residual virus present six months after infection. Six months," Furness added. "So this virus only begins in the lungs. And if all we’re going to talk about is lungs—and I really, really dislike that framing—then we can call it mild but I’m unprepared to do that."

      Vancouver Coastal Health also claimed in its statement that COVID-19 "spreads primarily through respiratory droplet transmission within a short range".

      This interpretation of COVID-19 has come under fire from many aerosol researchers, including Jose-Luis Jimenez at the University of Colorado Boulder.

      The Straight asked Vancouver Coastal Health for a list of the peer-reviewed studies that it relied on to support its position regarding HEPA filters. (The list is at the bottom of this paper and none include the word "filter" in the title.)

      "As you’re no doubt aware, the closed peer review process for scientific literature often takes months or years between submission and publication—it’s not designed for the rapid dissemination of critical information during a rapidly evolving global pandemic," Vancouver Coastal Health public-health communications leader Deana Lancaster wrote in an email to the Straight in response to the question.

      "Accordingly, a large volume of COVID-19 research has been published on preprint servers such as, which is sponsored by Yale University. Since you specified that you only wanted links to peer-reviewed literature, I have listed several of the most recent papers below that have helped to inform local decision-making, including one conducted in the VCH region.

      "However, given that decisions must be based on the most up-to-date research I’ve also included preprints, including another study recently conducted here. Below that, I have included a list of older studies that our medical health officers have used to guide decision-making related to schools throughout the pandemic. Since we’re now focused on measures specific to variants of concern I did not add the links. If interested, you can search by title."

      Vancouver Coastal Health sources





      Older studies

      • Boey, L., Roelants, M., Merckx, J., Hens, N., Desombere, I., Duysburgh, E., & Vandermeulen, C. (2021). Agedependent seroprevalence of SARS-CoV-2 antibodies in school-aged children from areas with low and high community transmission.
      • Bordi, L., Parisi, G., Sberna, G., Amendola, A., Mariani, B., Meoni, G. (2021). Effective screening strategy against SARS-CoV-2 on self-collected saliva samples in primary school setting: a pilot project. Journal of Infection. 
      • Buonsenso, D., De Rose, C., Moroni, R., & Valentini, P. (2021). SARS-CoV-2 infections in Italian schools: Preliminary findings after 1 month of school opening during the second wave of the pandemic. Frontiers in Pediatrics. 
      • COVID-Explained. (2020, Nov 9). Data overview: Child care centers, camps, and outbreaks
      • Ehrhardt, J., Ekinci, A., Krehl, H., Meincke, M., Finci, I., Klein, J., … Brockmann, S.O. (2020). Transmission of SARSCoV-2 in children aged 0 to 19 years in childcare facilities and schools after their reopening in May 2020, BadenWürttemberg, Germany. Eurosurveillance 25(36): pii=2001587.
      • European Centre for Disease Prevention and Control (2020, December 23). COVID-19 in children and the role of school settings in COVID-19 transmission.
      • Folkhälsomyndighete. (2020, May 27). Förekomst av covid-19 i olika yrkesgrupper.
      • Fong, M.W., Cowling, B.J., Leung, G.M., & Wu, P. (2020). Letter to the editor: COVID-19 cases among school-aged children and school-based measures in Hong Kong, July 2020. Eurosurveillance, 25(37).
      • Gilliam, W.S., Malik, A.A., Shafiq M., Klotz, M., Reyes, C., Humphries, J.E., … Omer, S.B. (2020). COVID-19 transmission in US child care programs. Pediatrics, 147(1), e2020031971.
      • Gutierrez, V.C., Hassard, F., Vu, M., Leitao, R., Burczynska, B., Wildeboer, D. … Cesare, M.D. (2021). Monitoring occurrence of SARS-CoV-2 in school populations: a wastewater-based approach. 
      • Hobbs, C.V., Martin, L.M., Kim, S.S., Kirmse, B.M., Haynie, L., McGraw, S., … Flannery, B. (2020). Factors associated with positive SARS-CoV-2 test results in outpatient health facilities and emergency departments among children and adolescents aged <18 years — Mississippi, September–November 2020. Morbidity and Mortality Weekly Report, 69, 1925-1929.
      • Hommes, F., van Loon, W., Thielecke, M., Abramovich, I., Lieber, S., Hammerich, R., … Mockenhaupt, F.P. (2020).
      • SARS-CoV-2 infection, risk perception, behaviour, and preventive measures at schools in Berlin, Germany, during the early post-lockdown phase: A cross-sectional study. International Journal of Environmental Research and Public Health, 18(5), 2739.
      • Institut national de santé publique du Québec. (2021, April). Vigie de la COVID-19 dans les services de garde éducatifs à l’enfance - Avril 2021.
      • Jones, R.D. (2020). COVID-19 trends in Florida K-12 schools, August 10 – November 14, 2020.
      • Kindzierski, S., van Loon, W., Theuring, S., Hommes, F., Thombansen, E., Böttcher, M. … & Gertler, M. (2021).
      • SARS-CoV-2 screening prevalence in educational staff in Berlin, Germany, June-December 2020. 
      • Köstner, C., Letzel, S., Eggert, V., Beutel, T., & Dietz, P. (2021). Comparing SARS-CoV-2 case rates between pupils, teachers and the general population: results from Germany. 
      • Update 17: August 12, 2021 4
      • Kowalsky, R. H., Fine, S., Eisenberg, M. (2021). Exclusion of SARS-CoV-2 from two Maine overnight camps JulyAugust 2020. Disaster Medicine and Public Health Preparedness. 
      • Lanier, W.A., Babitz, K.D., Collingwood, A., Graul, M.F., Dickson, S., Cunningham, L., … Hersh, A.L. (2021). COVID19 testing to sustain in-person instruction and extracurricular activities in high schools — Utah, November 2020–March 2021. Morbidity and Mortality Weekly Report, 70(21), 785-791.
      • Lewis, S.J., Dack, K., Relton, C.L., Munafò, M.R., & Smith, G.D. (2021). Risk of death among teachers in England and Wales during the Covid19 pandemic.
      • Llupià, A., Borràs-Santos, A., Guinovart, C., Utzet, M., Moriña, D., & Puig, J. (2021). SARS-CoV-2 transmission in students of public schools of Catalonia (Spain) after a month of reopening. PLoS One, 16(5), e0251593.
      • Ludvigsson, J.F., Engerström, L., Nordenhäll, C., & Larsson, E. (2021). Open schools, COVID-19, and child and teacher morbidity in Sweden. The New England Journal of Medicine, 384, 669-671.
      • Manny, E., Carroll, A., Charlton, C., Robinson, J., Subbarao, P., Azad, M.B., … Mandhane, P.J. (2020). Increased mask use and fewer gatherings associated with lower SARS-CoV-2 seropositivity among young school-age children. 
      • McCluskey, N. (2021). Private schooling after a year of COVID-19: How the private sector has fared and how to keep it healthy. 
      • Nachman, S., Brauner, G., Beleck, A., & Handel, A.S. (2021). Day camp in the time of COVID-19: What went right? 
      • National Institute for Public Health and the Environment (RIVM). (2021, March 19). Children, school and COVID-19.
      • Otte im Kampe, E., Lehfeld, A. S., Buda, S., Buchholz, U., & Haas, W. (2020). Surveillance of COVID-19 school outbreaks, Germany, March to August 2020. Eurosurveillance 25(38).
      • Pollock, N.R., Berlin, D., Smole, S.C., Madoff, L.C., Henderson, K., Larsen, E. … Lennon, N.J. (2021). Implementation of SARS-CoV2 screening in K-12 schools using in-school pooled molecular testing and deconvolution by rapid antigen test. 
      • Pray, I., Kocharian, A., Mason, J., Westergaard, R., & Meiman, J. (2021). Trends in outbreak-associated cases of COVID-19 — Wisconsin, March–November 2020. Morbidity and Mortality Weekly Report, 70(4), 114-117.
      • Robert Koch Institute. (2020, Nov 30). Coronavirus disease 2019 (COVID-19) daily situation report of the Robert Koch Institute.
      • Rytter, M.J.H., Nygaard, U., Mandic, I.N., Glenthøj, J.P., Schmidt, L.S., Cortes, D. … Kristensen, K. (2021). Prevalence of SARS-CoV-2 antibodies in Danish children and adults. The Pediatric Infectious Disease Journal, 40(4), e157-e159.
      • Smith-Norowitz, T.A., Kohlhoff, S., Hammerschlag, M. R. (2021). Coronavirus disease 2019 prevalence rates in reopened private schools in New York City: Impact of diagnostic methods. Acta Paediatrica. 
      • Smith-Norowitz, T.A., Norowitz, Y.M., Kohlhoff, S., & Hammerschlag, M.R. (2021). SARS-CoV-2 positivity rates are lower in school compared with local rates in Brooklyn, New York. Acta Paediatrica. 
      • Szépfalusi, Z., Schmidthaler, K., Sieber, J., Kopanja, S., Götzinger, F., Schoof, A. … Frischer, T. (2021). Lessons from low seroprevalence of SARS‐CoV‐2 antibodies in schoolchildren: a cross‐sectional study. Pediatric Allergy and Immunology. 
      • Thompson, D.A., Abbasizanjani, H., Fry, R., Marchant, E., Griffiths, L., Akbari, A., … Lyons, R. (2021). Staff-pupil SARS-CoV-2 infection pathways in schools: a population level linked data approach. 
      • Ulyte, A., Radtke, T., Abela, I.R., Haile, S.R., Blankenberger, J., Jung, R., … Kriemler, S. (2020). Variation in SARSCoV-2 seroprevalence in school-children across districts, schools and classes. 
      • Varma, J.K., Thamkittikasem, J., Whittemore, K., Alexander, M., Stephens, D.H., Arslanian, K. … Long, T.G. (2021).
      • COVID-19 infections among students and staff in New York City public schools. Pediatrics, 147(5). 
      • Villani, A., Coltella, L., Ranno, S., Bianchi di Castelbianco, F., Murru, P.M., Mazzone, T. … Concato, C. (2021). School in Italy: a safe place for children and adolescents. Italian Journal of Pediatrics, 47, 1-3.
      • Zimmerman, K., Akinboyo, I.C., Brookhart, A., Boutzoukas, A.E., McGann, K., Smith, M.J., … Benjamin Jr., D.K. (2020). Incidence and secondary transmission of SARS-CoV-2 infections in schools. Pediatrics. 
      • Zinszer, K., McKinnon, B., Bourque, N., Pierce, L., Saucier, A., Otis, A. … Quach, C. (2021). Seroprevalence of antiSARS-CoV-2 antibodies among school and daycare children: Baseline results from a cohort study in Montreal, Canada. 
      • Aiano, F, Mensah, A., McOwat, K., Obi, C., Vusirikala, A., Powell, A. … Saliba, V. (2021). COVID-19 outbreaks following full reopening of primary and secondary schools in England: retrospective, cross-sectional national surveillance. The Lancet Regional Health- Europe, 6, 100120.
      • Aizawa, Y., Shobukawa, Y., Tomiyama, N., Nakayama, H., Takahashi, M., Yanagita, J. … Saitoh, A. (2021). Coronavirus disease 2019 cluster originating in a primary school teachers’ room in Japan. 
      • Alberta Health Services. (2020, August 7). COVID-19 scientific advisory group rapid evidence report.
      • Armann, J.P., Kirsten, C., Galow, L., Kahre, E., Haag, L., Dalpke, A. (2021). SARS-CoV-2 transmissions in students and teachers: seroprevalence follow-up study in a German secondary school in November and December 2020. BMJ Paediatrics Open, 5, e001036.
      • Armann, J.P., Unrath, M., Kirsten, C., Lück, C., Dalpke, A.H., & Berner, R. (2020). SARS-CoV-2 IgG antibodies in adolescent students and their teachers in Saxony, Germany (SchoolCoviDD19): Persistent low seroprevalence and transmission rates between May and October 2020. 
      • Belavic, A., Dimnjakovic, J., Istvanovic, A., Svajda, M., Poljicanin, T., & Simetin, I.P. (2021). Re-opening schools in Croatia did not have a negative impact on children under 14, but it could not be ruled out in older children. Acta Paediatrica. 
      • Blaisdell, L.L., Cohn, W., Pavell, J.R., Rubin, D.S. & Vergales, J.E. (2020). Preventing and mitigating SARS-CoV-2 transmission – four overnight camps, Maine, June-August 2020. Morbidity and Mortality Weekly Report 69(35), 1216-1220.
      • Bosslet, G. T., Pollak, M., Jang, J.H., Roll, R., Sperling, M., & Khan, B. (2021). The effect of in-person primary and secondary school instruction on county-level SARS-CoV-2 spread in Indiana. Clinical Infectious Disease, ciab306.
      • Brandal, L.T., Ofitserova, T.S., Meijerink, H., Rykkvin, R., Lund, H.M., Hungnes, O., … Winje, B.A. (2021). Minimal transmission of SARS-CoV-2 from paediatric COVID-19 cases in primary schools, Norway, August to November 2020. Eurosurveillance, 26(1), 1-6.
      • Buja, A., Paganini, M., Cristofori, V., Baldovin, T., Fusinato, R., Bocucuzzo, G., … & Parpinel, M. (2021). Opening schools and trends in SARS-CoV-2 transmission in European countries. 
      • Buonsenso, D. & Graglia, B. (2021). High rates of SARS‐CoV‐2 transmission in a high‐school class. Journal of Paediatrics and Child Health, 57(2), 299-300.
      • Brown, N.E., Bryant-Genevier, J., Bandy, U., Browning, C.A., Berns, A.L., … Watson, J. (2020). Antibody responses after classroom exposure to teacher with coronavirus disease, March 2020. Emerging Infectious Diseases 26(9), 2263-2265.
      • Brurberg, K.G. (2020). The role of children in the transmission of SARS-CoV-2-19 – 1st update - a rapid review.
      • Oslo: Folkehelseinstituttet/Norwegian Institute of Public Health.
      • Cai, J., Wang, X., Zhao, J., Ge, Y., Xu, J., Tian, H., … Zeng, M. (2020). Comparison of clinical and epidemiological characteristics of asymptomatic and symptomatic SARS-CoV-2 infection in children. Virologica Sinica, 35, 803- 810.
      • Casini, L. & Roccetti, M. (2021). Reopening Italy’s schools in September 2020: A Bayesian estimation of the change in the growth rate of new SARS-CoV-2 cases. 
      • Chernozhukov, V., Kasahara, H., Schrimpf, P. (2021). The association of opening K-12 schools and colleges with the spread of COVID-19 in the United States: county-level panel data analysis. 
      • Children’s Task and Finish Group. (2020, December 17). Update to 4th Nov 2020 paper on children, schools and transmission.
      • Cooch, P., Watson, A., Olarte, A., Crawford, E., CLIAhub Consortium, DeRisi, J., … Bardach, N. (2020). Supervised self-collected SARS-CoV-2 testing in indoor summer camps to inform school reopening. 
      • Cooper, D.M., Messaoudi, I., Aizik, S., Camplain, R.L., Lopez, N.V., Ardo, J. … & Boden-Albala, B. (2021). SARSCoV-2 acquisition and immune pathogenesis among school-aged learners in four K-12 schools. 
      • Cordery, R., Reeves, L., Zhou, J., Rowan, A., Watber, P., Rosadas, C., … & Sriskandan, S. (2021). Transmission of SARS-CoV-2 by children attending school. Interim report on an observational, longitudinal sampling study of infected children, contacts, and the environment. 
      • Crowe, J., Schnaubelt, A. T., Schmidt-Bonne, S., Angell, K., Bai, J., Eske, T. … Broadhurst, M. J. (2021). Pilot program for test-based SARS-CoV-2 screening and environmental monitoring in an urban public school district. 
      • Danis, K., Epaulard, O., Bénet, T., Gaymard, A., Campoy, S., Bothelo-Nevers, E., … Saura, C. (2020). Cluster of coronavirus disease 2019 (COVID-19) in the French Alps, February 2020. Clinical Infectious Diseases 71(15): 825- 832.
      • Dawson, P., Worrell, M.C., Malone, S., Tinker, S.C., Fritz, S., Maricque, B. … CDC COVID-19 Surge Laboratory Group. (2021). Pilot investigation of SARS-CoV-2 secondary transmission in kindergarten through grade 12 schools implementing mitigation strategies — St. Louis County and City of Springfield, Missouri, December 2020. Morbidity and Mortality Weekly Report, 70(12), 449-455.
      • Department of Education, Department of Health and Telethon Kids Institute. (2021). DETECT schools study: Understanding the impact of COVID-19 in western Australian schools.
      • Desmet, S., Skinci, E., Wouters, I., Decru, B., Beuselinck, K., Malhotra-Kumar, S., & Theeten, H. (2020). No SARSCoV-2 carriage observed in children attending daycare centers during the first weeks of the epidemic in Belgium. Journal of Medical Virology, 93, 1828-1831.
      • Doron, S., Ingalls, R.R., Beauchamp, A., Boehm, J., Boucher, H.W., Chow, L.H. … Ciaranello, A. (2021). Weekly SARS-CoV-2 screening of asymptomatic students and staff to guide and evaluate strategies for safer in-person learning. 
      • Doyle, T., Kendrick, K., Troelstrup, T., Gumke, M., Edwards, J., Chapman, S., Propper, R., … Blackmore, C. (2021). COVID-19 in primary and secondary school settings during the first semester of school reopening – Florida, August – December 2020. Morbidity and Mortality Weekly Report, 70(12), 437-441.
      • Dub, T., Erra, E., Hagberg, L., Sarvikivi, E., Virta, C., Jarvinen, A., … Nohynek, H. (2020). Transmission of SARSCoV-2 following exposure in school settings: experience from two Helsinki area exposure incidents. 
      • Fadlallah, R., Jamal, D., Daher, N., Masri, R., & Hemadi, N. (2020 September 18). COVID-19 supplement on school re-opening (2 of 3): K2P evidence summary - Impact of school closure/ reopening and school management practices on COVID-19 pandemic. American University of Beirut Faculty of Health Sciences.
      • Falk, A., Benda, A., Falk, P., Steffen, S., Wallace, Z., & Høeg, T.B. (2021). COVID-19 cases and transmission in 17 K–12 schools — Wood County, Wisconsin, August 31–November 29, 2020. Morbidity and Mortality Weekly Report, 70, 136-140.
      • Falk, A., Benda, A., Falk, P., Steffen, S., DeCoster, M., Gandhi, M., & Høeg, T.B. (2021). Details of COVID-19 disease mitigation strategies in 17 K-12 schools in Wood County, Wisconsin. 
      • Fontanet, A., Grant, R., Tondeur, L., Madec, Y., Grzelak, L., Cailleau, I., … Hoen, B. (2020). SARS-CoV-2 infection in primary schools in northern France: A retrospective cohort study in an area of high transmission. 
      • Fontanet, A., Tondeur, L., Madec, Y., Grant, R., Besombes, C., Jolly, N., … Hoen, B. (2020). Cluster of COVID-19 in northern France: A retrospective closed cohort study. 
      • Fricchione, M.J., Seo, J.Y., & Arwady, M.A. (2020). Data-driven reopening of urban public education through Chicago’s tracking of COVID-19 school transmission. Public Health Management & Practice, 27(3), 229-232.
      • Gettings, J.R., Gold, J.A.W., Kimball, A., Forsberg, K., Scott, C., Uehara, A. … Vallabhaneni, S. (2021). SARS-CoV-2 transmission in a Georgia school district — United States, December 2020–January 2021. Clinical Infectious Diseases, ciab332.
      • Gillespie, D.L., Meyers, L.A., Lachmann, M., Redd, S.C., & Zenilman, J.M. (2021). The experience of two independent schools with in-person learning during the COVID- 19 pandemic. Journal of School Health, 91(5), 347-355.
      • Godøy, A., Grøtting, M.W., & Hart, R.K. (2021). Re-opening schools in a context of low COVID-19 contagion: Consequences for teachers, students and their parents. 
      • Goldhaber, D., Imberman, S.A., Hopkins, B., Brown, N., Harbatkin, E., & Kilbride, T. (2021). To what extent does inperson schooling contribute to the spread of COVID-19? Evidence from Michigan and Washington. National Bureau of Economic Research.
      • Goldstein, E., Lipsitch, M., & Cevik, M. (2020). On the effect of age on the transmission of SARS-CoV-2 in households, schools and the community. The Journal of Infectious Diseases, 223(3), 362-369.
      • Gras-Le Guen, C., Cohen, R., Rozenberg, J., Launay, E., Levy-Bruhl, D., & Delacourt, C. (2021). Reopening schools in the context of increasing COVID-19 community transmission: The French experience. Archives de Pédiatrie. 28(3), 178-185.
      • Haapanen, M., Renko, M., Artama, M., & Kuitunen, I. (2021). The impact of the lockdown and the re-opening of schools and day cares on the epidemiology of SARS-CoV-2 and other respiratory infections in children – A nationwide register study in Finland. EClinicalMedicine, 34, 100807.
      • Harris, D.N., Ziedan, E., & Hassig, S. (2021, January 4). The effects of school reopenings on COVID-19 hospitalizations. National Center for Research on Education Access and Choice.
      • Health Information and Quality Authority. (2020, August 21). Evidence summary for potential for children to contribute to transmission of SARS-CoV-2.
      • Heavey, L., Casey, G., Kelly, C., Kelly, D., & McDarby, G. (2020). No evidence of secondary transmission of COVID19 from children attending school in Ireland, 2020. Eurosurveillance 25(21), pii=2000903.
      • Heudorf, U., Steul, K., Walczok, A., Gottschalk, R. (2021). Children and COVID-19 - Data from mandatory reporting and results of contact person testing in daycare centers and schools in Frankfurt am Main, Germany, AugustDecember 2020. Monatsschr Kinderheilkd. 
      • Hoch, M., Vogel, S., Kolberg, L., Dick, E., Fingerle, V., Eberle, U., … von Both, U. (2021). Weekly SARS-CoV-2 sentinel in primary schools, kindergartens and nurseries, June to November 2020, Germany. 
      • Hoehl, S., Kreutzer, E., Schenk, B., Westhaus, S., Foppa, I., Herrmann, I., … Ciesek, S. (2021). Longitudinal testing for respiratory and gastrointestinal shedding of SARS-CoV-2 in day care centres in Hesse, Germany. Clinical Infectious Diseases. 
      • Hoehl, S., Schenk, B., Rudych, O., Göttig, S., Foppa, I., Kohmer, N., … Ciesek, S. (2020). At-home self-testing of teachers with a SARS-CoV-2 rapid antigen test to reduce potential transmissions in schools. 
      • Ingelbeen, B., Peckeu, L., Laga, M., Hendrix, I., Neven, I., van der Sande, M.A.B., & van Kleef, E. (2021). Reducing contacts to stop SARS-CoV-2 transmission during the second pandemic wave in Brussels, Belgium, August to November 2020. Eurosurveillance, 26(7), 1-7.
      • Institut national de sante publiqué Québec. (2020, May 21). Revue rapide de la littérature scientifique - COVID-19 chez les enfants: facteurs de risque d’infections sévères et potentiel de transmission.
      • Ismail, S.A., Saliba, V., Lopez Bernal, J., Ramsay, M.E., & Ladhani, S.N. (2020). SARS-CoV-2 infection and transmission in educational settings: a prospective, cross-sectional analysis of infection clusters and outbreaks in England. The Lancet Infectious Diseases, 21(3), 344-353.
      • Isphording, I. E., Lipfert, M., & Pestel, N. (2021). Does re-opening schools contribute to the spread of SARS-CoV-2? Evidence from staggered summer breaks in Germany. Collaborative Research Center Transregio 224, University of Bonn & University of Mannheim.
      • Jordan, I., Fernandez de Sevilla, M., Fumado, V., Bassat, Q., Bonet-Carne, E., Fortuny, C., … & Gratacós, E. (2021). Transmission of SARS-CoV-2 infection among children in summer schools applying stringent control measures in Barcelona, Spain. Clinical Infectious Diseases, ciab227.
      • Kim, C., McGee, S., Khuntia, S., Elnour, A., Johnson-Clarke, F., Mangla, A. … Nesbitt, L. (2021). Characteristics of COVID-19 cases and outbreaks at child care facilities — District of Columbia, July–December 2020. Morbidity and Mortality Weekly Report, 70(20), 744-748.
      • Körner, R.W. & Weber, L.T. (2021). Prevalence of COVID-19 among children and adolescents while easing lockdown restrictions in Cologne, North Rhine-Westphalia, Germany. Klinische Pädiatrie. 
      • Kriemler, S., Ulyte, A., Ammann, P., Peralta, G.P., Berger, C., Puhan, M.A., Radtke, T. (2020). Surveillance of acute SARS-CoV-2 infections in school children and point-prevalence during a time of high community transmission in Switzerland. Frontiers in Pediatrics, 9, 645577.
      • Kriger, O., Lustig, Y., Cohen, C., Amit, S., Biber, A., Barkai, G., … Regev-Yochay, G. (2020). The Sheba Medical Center healthcare workers' children's school: can we open schools safely?. Clinical Microbiology and Infection. 
      • Krishnaratne, S., Pfadenhauer, L.M., Coenen, M., Geffert, K., Jung-Sievers, C., Klinger, C., … Burns, J. (2020). Measures implemented in the school setting to contain the COVID-19 pandemic: a rapid scoping review. Cochrane Database Systematic Reviews, 12.
      • Lachassinne, E., de Pontual, L., Caseris, M., Lorrot, M., Guilluy, C., Naud, A. … COVIDOCRECHE collaborators. (2021). SARS-CoV-2 transmission among children and staff in daycare centres during a nationwide lockdown in France: a cross-sectional, multicentre, seroprevalence study. The Lancet Child & Adolescent Health, 5(4), 256-264.
      • Ladhani, S.N., Baawuah, F., Beckmann, J., Okike, I.O., Ahmad, S., Garstang, J. … Ramsay, M.E. (2021). SARS-CoV2 infection and transmission in primary schools in England in June-December, 2020 (sKIDs): an active, prospective surveillance study. Lancet Child & Adolescent Health, 5(6), 417-427.
      • Ladhani, S.N., Ireland, G., Baawuah, F., Beckmann, J., Okike, I.O., Ahmad, S. … Ramsay, M.E. (2021). SARS-CoV-2 infection, antibody positivity and seroconversion rates in staff and students following full reopening of secondary schools in England: A prospective cohort study, September–December 2020. EClinicalMedicine, 37, 100948.
      • Larosa, E., Djuric, O., Cassinadri, M., Cilloni, S., Bisaccia, E., Vicentini, M., … Reggio Emilia Covid-19 Working Group. (2020). Secondary transmission of COVID-19 in preschool and school settings in northern Italy after their reopening in September 2020: a population-based study. Eurosurveillance, 25(49): pii=2001911.
      • Lichand, G., Dória, C.A., Cossi, J., & Leal-Neto, O. (2021). Reopening schools in the pandemic did not increase COVID-19 incidence and mortality in Brazil. 
      • Link-Gelles, R., DellaGrotta, A.L., Molina, C., Clyne, A., Campagna, K., Lanzieri, T.M., … Bandy, U. (2020). Limited secondary transmission of SARS-CoV-2 in child care programs -Rhode Island, June 1-July 31, 2020. Morbidity and Mortality Weekly Report 69(34), 1170-1172.
      • Liu, D., Lin, G., Sun, X., Du, Y., Liu, H., & Qu, M. (2021). Different school reopening plans on coronavirus disease 2019 case growth rates in the school setting in the United States. Journal of School Health, 91, 370-375.
      • Lopez, A.S., Hill, M., Antezano, J., Vilven, D., Rutner, T., Bogdanow, L., … Tran, C.H. (2020). Transmission dynamic of COVID-19 outbreaks associated with child care facilities – Salt Lake City, Utah, April-July 2020. Morbidity and Mortality Weekly Report 69(37), 1319–1323.
      • Lübke, N., Schupp, A.-K., Bredahl, R., Kraus, U., Hauka, S., Andrée, M., … & Timm, J. (2021). Screening for SARSCoV-2 infections in daycare facilities for children in a large city in Germany. 
      • Ludvigsson, J.F. (2020). Children are unlikely to be the main drivers of the COVID-19 pandemic – A systematic review. Acta Paediatrica 109(8), 1525-1530.
      • Macartney, K., Quinn, H.E., Pillsbury, A.J., Koirala, A., Deng, L., Winkler, N., … Chant, K. (2020). Transmission of SARS-CoV-2 in Australian educational settings: a prospective cohort study. The Lancet Child & Adolescent Health, 4(11), 807-816.
      • Mensah, A., Sinnathamby, M., Zaidi, A., Coughlan, L., Ismail, S.A., Ramsay, M.E., ... Ladhani, S.N. (2021). SARSCoV-2 infections in children following the full re-opening of schools and the impact of national lockdown: Prospective, national observational cohort surveillance, July-December 2020, England. Journal of Infection, 82, 67-74.
      • Miron, O., Yu, K.H., Wilf-Miron, R., Kohane, I., & Davidovitch, N. (2020). COVID-19 infections following physical school reopening. Archives of Disease in Childhood, 106, e34.
      • Mossong, J., Mombaerts, L., Veiber, L., Pastore, J., LeCoroller, G., Schnell, M., … Wilmes, P. (2020). SARS-CoV-2 transmission in educational settings during an early summer epidemic wave in Luxembourg. 
      • National Centre for Immunisation Research and Surveillance. (2021, March 9). COVID-19 in schools and early childhood education and care services – the Term 4 experience in NSW.
      • National Centre for Immunisation Research and Surveillance. (2020, October 21). COVID-19 in schools and early childhood education and care services – the Term 3 experience in NSW.
      • National Centre for Immunisation Research and Surveillance. (2020, July 31). COVID-19 in schools and early childhood education and care services – the Term 2 experience in NSW.
      • Nelson, E.J., McKune, S.L., Ryan, K.A., Lednicky, J.A., Crowe, S.R., Myers, P.D., & Morris Junior, J.G. (2021). SARS-CoV-2 positivity on or after 9 days among quarantined student contacts of confirmed cases. JAMA, 325(15), 1561-1562.
      • Okarska-Napierala, M., Mańdziuk, J., & Kuchar, E. (2020). SARS-CoV-2 cluster in Nursery, Poland. Emerging Infectious Disease, 27(1), 317-319.
      • Peaper, D.R., Murdzek, C., Oliveira, C., & Murray, T. (2020). Severe acute respiratory syndrome coronavirus 2 testing in children in a large regional US health system during the coronavirus disease 2019 pandemic. The Pediatric Infectious Disease Journal, 40(3), 175-181.
      • Pray, I.W., Gibbons-Burgener, S.N., Rosenberg, A.Z., Cole, D., Borenstein, S., Bateman, A., … Westergaard, R.P. (2020). COVID-19 outbreak at an overnight summer school retreat ― Wisconsin, July–August 2020. Morbidity and Mortality Weekly Report 69(43): 1600-1604.
      • Public Health Agency of Canada. (2021, May 4). Rapid review on the impact of school closures and re-openings on COVID-19 transmission.
      • Public Health Agency of Sweden. (2020, July 7). COVID-19 in schoolchildren: A comparison between Finland and Sweden.
      • Public Health England. (2020, July 28). Transmission of COVID-19 in school settings and interventions to reduce the transmission: a rapid review.
      • Rajmil, L. (2020). Role of children in the transmission of the COVID-19 pandemic: a rapid scoping review. BMJ Paediatrics Open, 4(1), e000722.
      • Reinbold, G.W. (2021). Effect of Fall 2020 K-12 instruction types on COVID-19 cases, hospital admissions, and deaths in Illinois counties. American Journal of Infection Control. 
      • Rozhnova, G., van Dorp, C.H., Bruijning-Verhagen, P., Bootsma, M.C.J., van de Wijgert, J.H.H.M., Bonten, M.J.M., Kretzschmar, M.E. (2020). Model-based evaluation of school- and non-school-related measures to control the COVID-19 pandemic. Nature Communications, 12, 1614.
      • Russell, F.M., Ryan, K., Snow, K., Danchin, M., Mulholland, K., & Goldfeld, S. (2020). Methods to analyze DHHS data. In, COVID-19 in Victorian Schools: An analysis of child-care and school outbreak data and evidence-based recommendations for opening schools and keeping them open (pp. 31-52). Murdoch Children’s Research Institute and The University of Melbourne.
      • Schoeps, A., Hoffmann, D., Tamm, C., Vollmer, B., Haag, S., Kaffenberger, T., ... Zanger, P. (2021). COVID-19 transmission in educational institutions August to December 2020 in Germany: a study of index cases and close contact cohorts. 
      • Smith-Norowitz, T.A., Hammerschlag, M.R., & Kohlhoff, S. (2021). Coronavirus disease 2019 (COVID-19) infection rates in a private school in Brooklyn, New York. Acta Paediatrica, 110(5), 1569-1570.
      • Somekh, I., Boker, L. K., Shohat, T., Pettoello-Mantovani, M., Simões, E.A.F., & Somekh, E. (2021). Comparison of COVID-19 incidence rates before and after school re-opening in Israel. JAMA Network Open, 4(4), e217105.
      • Somekh, I., Shohat, T., Boker, L.K., Simões, E.A.F., & Somekh, E. (2021). Reopening schools and the dynamics of SARS-CoV-2 infections in Israel: A nationwide study. Clinical Infectious Diseases. 
      • Soto, J.C., Barakat, M., Hutter, J.A., Kiely, M., Moreira, S., Shapiro, B.J. … Lessard, R. (2021). Outbreak investigation of SARS-CoV-2 transmission in an emergency childcare centre. Canadian Journal of Public Health, 112(4), 566-575.
      • Stage, H.B., Shingleton, J., Ghosh, S., Scarabel, F., Pellis, L., & Finnie, T. (2020). Shut and re-open: the role of schools in the spread of COVID-19 in Europe. 
      • Stein-Zamir, C., Abramson, N., Shoob, H., Libal, E., Bitan, M., Cardash, T., … Miskin, I. (2020). A large COVID-19 outbreak in a high school 10 days after schools’ reopening, Israel, May 2020. Eurosurveillance 25(29): pii=2001352.
      • Suh, H. H., Meehan, J., Blaisdell, L., & Browne, L. (2021). Effectiveness of non-pharmaceutical interventions on child and staff COVID-19 cases in US summer camps. 
      • Suk, J.E., Vardavas, C., Nikitara, K., Phalkey, R., Leonardi-Bee, J., Pharris, A., … Semenza, J.C. (2020). The role of children in the transmission chain of SARS-CoV-2: a systematic review and update of current evidence. 
      • Sulaiman, F., Coomaran, V., Muhajarine, N., Dalidowicz, M., & Miller, L. (2021). What are the effects of the new COVID variants on transmission and school reopenings in pediatric populations? Saskatchewan Health Authority.
      • Szablewski, C.M., Chang, K.T., Brown, M.M., Chu, V.T., Yousaf, A.R., Anyalechi, N., … Stewart, R.J. (2020). SARSCoV-2 transmission and infection among attendees of an overnight camp. Morbidity and Mortality Weekly Report 69(31): 1023-1025.
      • Theuring, S., Thielecke, M., van Loon, W., Hommes, F., Hülso, C., von der Haar, A. … BECOSS Study Group.
      • (2021). SARS-CoV-2 infection and transmission in school settings during the second wave in Berlin, Germany: a cross-sectional study. 
      • Thielecke, M., Theuring, S., van Loon, W., Hommes, F., Mall, M.A., Rosen, A., … Mockenhaupt, F.P. (2021). SARSCoV-2 infections in kindergartens and associated households at the start of the second wave in Berlin, Germany – a cross sectional study. European Journal of Public Health, ckab079.
      • Tönshoff, B., Müller, B., Elling, R., Renk, H., Meissner, P., Hengel, H. … Kräusslich, H.-G. (2021). Prevalence of SARS-CoV-2 infection in children and their parents in southwest Germany. JAMA Pediatrics. 
      • Torres, J.P., Piñera, C., De La Maza, V., Lagomarcino, A.J., Simian, D., Torres, B., … O’Ryan, M. (2020). SARS-CoV2 antibody prevalence in blood in a large school community subject to a COVID-19 outbreak: a cross-sectional study. Clinical Infectious Diseases. 
      • Ulyte, A., Radtke, T., Abela, I.A., Haile, S.R., Berger, C., Huber, M., … Kriemler, S. (2021). Clustering and longitudinal change in SARS-CoV-2 seroprevalence in schoolchildren: prospective cohort study of 55 schools in Switzerland. BMJ, 372, n616.
      • Viner, R.M., Russell, S.J., Croker, H., Packer, J., Ward, J., Stansfield, C., … Booy, R. (2020). School closure and management practices during coronavirus outbreaks including COVID-19: a rapid systematic review. The Lancet Child & Adolescent Health, 4(5), 397–404.
      • Vlachos, J., Hertegård, & Svaleryd, H.B. (2021). The effects of school closures on SARS-CoV-2 among parents and teachers. Proceedings of the National Academy of Sciences of the United States of America, 118(9), e2020834118.
      • Volpp, K.G., Kraut, B.H., Ghosh, S., & Neatherlin, J. (2021). Minimal SARS-CoV-2 transmission after implementation of a comprehensive mitigation strategy at a school – New Jersey, August 20 – November 27, 2020. Morbidity and Mortality Weekly Report, 70(11), 377-381.
      • von Bismarck-Osten, C., Borusyak, K., & Schönberg, U. (2021). The role of schools in transmission of the SARSCoV-2 virus: Quasi-experimental evidence from Germany. Centre for Research and Analysis of Migration (CReAM) & Department of Economics, University College London.
      • Walsh, S., Chowdhury, A., Russell, S., Braithwaite, V., Ward, J., Waddington, … Mytton, O. (2021). Do school closures reduce community transmission of COVID-19? A systematic review or observational studies. 
      • White, P., Ceannt, R., Kennedy, E., O'Sullivan, M.B., Ward, M., & Collins, A. (2021). Children are safe in schools: a review of the Irish experience of reopening schools during the COVID-19 pandemic. Public Health, 195, 158-160.
      • White, P., O'Sullivan, M.B., Murphy, N., Stapleton, J., Dillon, A., Brennan, A., … Sheahan, A. (2021). An investigation into the rates of transmission of SARS‐CoV‐2 during the first 6 weeks of the 2020–2021 academic year in primary and post‐primary schools in Cork and Kerry, Ireland. Irish Journal of Medical Science. 
      • Willeit, P. Krause, R., Lamprecht, B., Berghold, A., Hanson, B., Stelzl, E., … & Wagner, M. (2021). Prevalence of RTqPCR-detected SARS-CoV-2 infection at schools: First results from the Austrian School-SARS-CoV-2 prospective cohort study. The Lancet Regional Health – Europe, 5, 100086.
      • Xu, W., Li, X., Dozier, M., He, Y., Kirolos, A., Lang, Z., … Theodoratou, E. (2020). What is the evidence for transmission of COVID-19 by children in schools? A living systematic review. Journal of Global Health, 10(2): 021104.
      • Yoon, Y., Choi, G.J., Kim, J.Y., Kim, K.R., Park, H., Chun, J.K., & Kim, Y.J. (2020). Childcare exposure to severe acute respiratory syndrome coronavirus 2 for 4-year-old presymptomatic child, South Korea. Emerging Infectious Diseases, 27(2), 341-347.
      • Yoon, Y., Kim, K.R., Park, H., Kim, S.Y., & Kim, Y.J. (2020). Stepwise school opening online and off-line and an impact on the epidemiology of COVID-19 in the pediatric population. Journal of Korean Medical Sciences, 35(46): e414.
      • Yung, C.H., Kam, K., Nadua, K.D., Chong, C.Y., Tan, N.W.H., Li, J., … Ng, K.C. (2020). Novel coronavirus 2019 transmission risk in educational settings. Clinical Infectious Diseases, 72(6), 1055-1058.