SARS-CoV-2 Infections Associated With School Closures and Community Interventions | Infectious Diseases | JN Learning | AMA Ed Hub [Skip to Content]
[Skip to Content Landing]

Simulation-Based Estimation of SARS-CoV-2 Infections Associated With School Closures and Community-Based Nonpharmaceutical Interventions in Ontario, Canada

Educational Objective
To identify the key insights or developments described in this article
1 Credit CME
Key Points

Question  What is the association of school reopening or closure with incident and cumulative COVID-19 case numbers compared with other community-based nonpharmaceutical interventions?

Findings  In this decision analytical modelling study of a synthetic population of 1 000 000 individuals in Ontario, Canada, compared with community-based nonpharmaceutical interventions, school closure was associated with a small change in estimated COVID-19 incidence trajectories and cumulative case counts.

Meaning  These findings suggest that community-based interventions to reduce COVID-19 case counts should take precedence over school closure.


Importance  Resurgent COVID-19 cases have resulted in the reinstitution of nonpharmaceutical interventions, including school closures, which can have adverse effects on families. Understanding the associations of school closures with the number of incident and cumulative COVID-19 cases is critical for decision-making.

Objective  To estimate the association of schools being open or closed with the number of COVID-19 cases compared with community-based nonpharmaceutical interventions.

Design, Setting, and Participants  This decision analytical modelling study developed an agent-based transmission model using a synthetic population of 1 000 000 individuals based on the characteristics of the population of Ontario, Canada. Members of the synthetic population were clustered into households, neighborhoods, or rural districts, cities or rural regions, day care facilities, classrooms (ie, primary, elementary, or high school), colleges or universities, and workplaces. Data were analyzed between May 5, 2020, and October 20, 2020.

Exposures  School reopening on September 15, 2020, vs schools remaining closed under different scenarios for nonpharmaceutical interventions.

Main Outcomes and Measures  Incident and cumulative COVID-19 cases between September 1, 2020, and October 31, 2020.

Results  Among 1 000 000 simulated individuals, the percentage of infections among students and teachers acquired within schools was less than 5% across modeled scenarios. Incident COVID-19 case numbers on October 31, 2020, were 4414 (95% credible interval [CrI], 3491-5382) cases in the scenario with schools remaining closed and 4740 (95% CrI, 3863-5691) cases in the scenario for schools reopening, with no other community-based nonpharmaceutical intervention. In scenarios with community-based nonpharmaceutical interventions implemented, the incident case numbers on October 31 were 714 (95% CrI, 568-908) cases for schools remaining closed and 780 (95% CrI, 580-993) cases for schools reopening. When scenarios applied the case numbers observed in early October in Ontario, the cumulative case numbers were 777 (95% CrI, 621-993) cases for schools remaining closed and 803 (95% CrI, 617-990) cases for schools reopening. In scenarios with implementation of community-based interventions vs no community-based interventions, there was a mean difference of 39 355 cumulative COVID-19 cases by October 31, 2020, while keeping schools closed vs reopening them yielded a mean difference of 2040 cases.

Conclusions and Relevance  This decision analytical modeling study of a synthetic population of individuals in Ontario, Canada, found that most COVID-19 cases in schools were due to acquisition in the community rather than transmission within schools and that the changes in COVID-19 case numbers associated with school reopenings were relatively small compared with the changes associated with community-based nonpharmaceutical interventions.

Sign in to take quiz and track your certificates

Buy This Activity

JN Learning™ is the home for CME and MOC from the JAMA Network. Search by specialty or US state and earn AMA PRA Category 1 CME Credit™ from articles, audio, Clinical Challenges and more. Learn more about CME/MOC

Article Information

Accepted for Publication: February 6, 2021.

Published: March 31, 2021. doi:10.1001/jamanetworkopen.2021.3793

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Naimark D et al. JAMA Network Open.

Corresponding Author: David Naimark, MD, MSc, Sunnybrook Health Sciences Centre, 1929 Bayview Ave, Room 386, Toronto, ON M4G 3E8, Canada (

Author Contributions: Dr Naimark had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Naimark, Mishra, Barrett, Ximenes, Sander.

Acquisition, analysis, or interpretation of data: Naimark, Mishra, Khan, Mac, Ximenes, Sander.

Drafting of the manuscript: Naimark, Ximenes.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Naimark, Mishra.

Obtained funding: Naimark, Ximenes, Sander.

Administrative, technical, or material support: Barrett, Khan, Mac.

Conflict of Interest Disclosures: Dr Barrett reported receiving personal fees from Xenios outside the submitted work. No other disclosures were reported.

Funding/Support: This research was supported by COVID-19 Rapid Research Funding (grant No. C-291-2431272-SANDER) through the Ontario Ministry of Health, Ontario Together. Dr Sander is supported in part by a Canada Research Chair in Economics of Infectious Diseases award (grant No. CRC-950-232429). Dr Mishra is supported by a Tier 2 Canada Research Chair in Mathematical Modeling and Program Science award.

Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: Richard Shillington, PhD (Statistics Canada), helped with queries of the Social Policy Simulation Database/Model, and Al Chrosny, PhD (TreeAge), provided technical help with the transmission model’s software platform. They were not compensated for their work.

Isfeld-Kiely  H , Moghadas  S .  Effectiveness of School Closure for the Control of Influenza: A Review of Recent Evidence. National Collaborating Centre for Infection Diseases; 2014.
Qiu  H , Wu  J , Hong  L , Luo  Y , Song  Q , Chen  D .  Clinical and epidemiological features of 36 children with coronavirus disease 2019 (COVID-19) in Zhejiang, China: an observational cohort study.   Lancet Infect Dis. 2020;20(6):689-696. doi:10.1016/S1473-3099(20)30198-5PubMedGoogle ScholarCrossref
Davies  NG , Kucharski  AJ , Eggo  RM , Gimma  A , Edmunds  WJ ; Centre for the Mathematical Modelling of Infectious Diseases COVID-19 working group.  Effects of non-pharmaceutical interventions on COVID-19 cases, deaths, and demand for hospital services in the UK: a modelling study.   Lancet Public Health. 2020;5(7):e375-e385. doi:10.1016/S2468-2667(20)30133-XPubMedGoogle ScholarCrossref
Koo  JR , Cook  AR , Park  M ,  et al.  Interventions to mitigate early spread of SARS-CoV-2 in Singapore: a modelling study.   Lancet Infect Dis. 2020;20(6):678-688. doi:10.1016/S1473-3099(20)30162-6PubMedGoogle ScholarCrossref
Banholzer  N , van Weenen  E , Kratzwald  B ,  et al  Impact of non-pharmaceutical interventions on documented cases of COVID-19.   medRxiv. Preprint posted online April 28, 2020. doi:10.1101/2020.04.16.20062141Google Scholar
Effler  PV , Carcione  D , Giele  C , Dowse  GK , Goggin  L , Mak  DB .  Household responses to pandemic (H1N1) 2009-related school closures, Perth, Western Australia.   Emerg Infect Dis. 2010;16(2):205-211. doi:10.3201/eid1602.091372PubMedGoogle ScholarCrossref
Basurto-Dávila  R , Garza  R , Meltzer  MI ,  et al.  Household economic impact and attitudes toward school closures in two cities in Argentina during the 2009 influenza A (H1N1) pandemic.   Influenza Other Respir Viruses. 2013;7(6):1308-1315. doi:10.1111/irv.12054PubMedGoogle ScholarCrossref
Gift  TL , Palekar  RS , Sodha  SV ,  et al; Pennsylvania H1N1 Working Group.  Household effects of school closure during pandemic (H1N1) 2009, Pennsylvania, USA.   Emerg Infect Dis. 2010;16(8):1315-1317. doi:10.3201/eid1608.091827PubMedGoogle ScholarCrossref
Epson  EE , Zheteyeva  YA , Rainey  JJ ,  et al.  Evaluation of an unplanned school closure in a Colorado school district: implications for pandemic influenza preparedness.   Disaster Med Public Health Prep. 2015;9(1):4-8. doi:10.1017/dmp.2015.3PubMedGoogle ScholarCrossref
Public Health Ontario.  Negative Impacts of Community-Based Public Health Measures During a Pandemic (e.g., COVID-19) on Children and Families. Ontario Agency for Health Protection and Promotion; 2020.
Statistics Canada. Social policy simulation database/model (SPSDM) [Canada] version 28.0.1. Accessed February 26, 2021.
Public Health Ontario. COVID-19 seroprevalence summary: COVID-19 seroprevalence in Ontario: March 27, 2020 to June 30, 2020. Accessed February 26, 2021.
Brisson  M , Gingras  G , Drolet  M , Laprise  JF ; group de modélisation COVID-19 ULAVAL/INSPQ. Modélisation de l’évolution de la COVID-19 au Québec. Accessed February 26, 2021.
Bi  Q , Wu  Y , Mei  S ,  et al.  Epidemiology and transmission of COVID-19 in 391 cases and 1286 of their close contacts in Shenzhen, China: a retrospective cohort study.   Lancet Infect Dis. 2020;20(8):911-919. doi:10.1016/S1473-3099(20)30287-5PubMedGoogle ScholarCrossref
Gostic  K , Gomez  ACR , Mummah  RO , Kucharski  AJ , Lloyd-Smith  JO .  Estimated effectiveness of symptom and risk screening to prevent the spread of COVID-19.   Elife. 2020;9:e55. doi:10.7554/eLife.55570PubMedGoogle Scholar
Kucharski  AJ , Klepac  P , Conlan  AJK ,  et al; CMMID COVID-19 working group.  Effectiveness of isolation, testing, contact tracing, and physical distancing on reducing transmission of SARS-CoV-2 in different settings: a mathematical modelling study.   Lancet Infect Dis. 2020;20(10):1151-1160. doi:10.1016/S1473-3099(20)30457-6PubMedGoogle ScholarCrossref
Voinsky  I , Baristaite  G , Gurwitz  D .  Effects of age and sex on recovery from COVID-19: Analysis of 5769 Israeli patients.   J Infect. 2020;81(2):e102-e103. doi:10.1016/j.jinf.2020.05.026PubMedGoogle ScholarCrossref
Li  W , Zhang  B , Lu  J ,  et al.  The characteristics of household transmission of COVID-19.   Clin Infect Dis. 2020;71(8):1943-1946. doi:10.1093/cid/ciaa450PubMedGoogle ScholarCrossref
Cheng  HY , Jian  SW , Liu  DP , Ng  TC , Huang  WT , Lin  HH ; Taiwan COVID-19 Outbreak Investigation Team.  Contact tracing assessment of COVID-19 transmission dynamics in Taiwan and risk at different exposure periods before and after symptom onset.   JAMA Intern Med. 2020;180(9):1156-1163. doi:10.1001/jamainternmed.2020.2020PubMedGoogle ScholarCrossref
Tuite  AR , Fisman  DN , Greer  AL .  Mathematical modelling of COVID-19 transmission and mitigation strategies in the population of Ontario, Canada.   CMAJ. 2020;192(19):E497-E505. doi:10.1503/cmaj.200476PubMedGoogle ScholarCrossref
Chu  DK , Akl  EA , Duda  S , Solo  K , Yaacoub  S , Schünemann  HJ ; COVID-19 Systematic Urgent Review Group Effort (SURGE) study authors.  Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis.   Lancet. 2020;395(10242):1973-1987. doi:10.1016/S0140-6736(20)31142-9PubMedGoogle ScholarCrossref
Ontario Ministry of Education. Types of child care. Accessed February 26, 2021.
Ontario Ministry of Education. Education facts, 2018-2019 (preliminary). Accessed February 26, 2021.
Viner  RM , Russell  SJ , Croker  H ,  et al.  School closure and management practices during coronavirus outbreaks including COVID-19: a rapid systematic review.   Lancet Child Adolesc Health. 2020;4(5):397-404. doi:10.1016/S2352-4642(20)30095-XPubMedGoogle ScholarCrossref
Levinson  M , Cevik  M , Lipsitch  M .  Reopening primary schools during the pandemic.   N Engl J Med. 2020;383(10):981-985. doi:10.1056/NEJMms2024920PubMedGoogle ScholarCrossref
Zimmerman  KO , Akinboyo  IC , Brookhart  MA ,  et al; ABC Science Collaborative.  Incidence and secondary transmission of SARS-CoV-2 infections in schools.   Pediatrics. Published online January 8, 2021. doi:10.1542/peds.2020-048090PubMedGoogle Scholar
Ismail  SA , Saliba  V , Lopez Bernal  J , Ramsay  ME , Ladhani  SN .  SARS-CoV-2 infection and transmission in educational settings: a prospective, cross-sectional analysis of infection clusters and outbreaks in England.   Lancet Infect Dis. 2020;3099(20):1-10. doi:10.2139/ssrn.3675431PubMedGoogle Scholar
Falk  A , Benda  A , Falk  P , Steffen  S , Wallace  Z , Høeg  TB .  COVID-19 cases and transmission in 17 K-12 schools—Wood County, Wisconsin, August 31-November 29, 2020.   MMWR Morb Mortal Wkly Rep. 2021;70(4):136-140. doi:10.15585/mmwr.mm7004e3PubMedGoogle ScholarCrossref
Flasche  S , Edmunds  WJ .  The role of schools and school-aged children in SARS-CoV-2 transmission.   Lancet Infect Dis. 2020;3099(20):3-4. doi:10.1016/S1473-3099(20)30927-0PubMedGoogle Scholar
Danis  K , Epaulard  O , Bénet  T ,  et al; Investigation Team.  Cluster of coronavirus disease 2019 (COVID-19) in the French Alps, February 2020.   Clin Infect Dis. 2020;71(15):825-832. doi:10.1093/cid/ciaa424PubMedGoogle ScholarCrossref
Yung  CF , Kam  KQ , Nadua  KD ,  et al.  Novel coronavirus 2019 transmission risk in educational settings.   Clin Infect Dis. 2020;3-6:ciaa794. doi:10.1093/cid/ciaa794PubMedGoogle Scholar
Heavey  L , Casey  G , Kelly  C , Kelly  D , McDarby  G .  No evidence of secondary transmission of COVID-19 from children attending school in Ireland, 2020.   Euro Surveill. 2020;25(21):1-4. doi:10.2807/1560-7917.ES.2020.25.21.2000903PubMedGoogle ScholarCrossref
Fontanet  A , Grant  R , Tondeur  L ,  et al  SARS-CoV-2 infection in primary schools in northern France: a retrospective cohort study in an area of high transmission.   medRxiv. 2020. doi:10.1101/2020.06.25.20140178Google Scholar
Brown  NE , Bryant-Genevier  J , Bandy  U ,  et al.  Antibody responses after classroom exposure to teacher with coronavirus disease, March 2020.   Emerg Infect Dis. 2020;26(9):2263-2265. doi:10.3201/eid2609.201802PubMedGoogle ScholarCrossref
Hildenwall  H , Luthander  J , Rhedin  S ,  et al.  Paediatric COVID-19 admissions in a region with open schools during the two first months of the pandemic.   Acta Paediatr. 2020;109(10):2152-2154. doi:10.1111/apa.15432PubMedGoogle ScholarCrossref
National Centre for Immunisation Research and Surveillance. COVID-19 in schools and early childhood education and care services—the term 3 experience in NSW. Accessed February 26, 2021.
Public Health Ontario.  COVID-19 Pandemic School Closure and Reopening Impacts. Ontario Agency for Health Protection and Promotion; 2020.
Forbes  H , Morton  CE , Bacon  S ,  et al  Association between living with children and outcomes from COVID-19: an OpenSAFELY cohort study of 12 million adults in England.   medRxiv. Preprint posted online November 2, 2020. doi:10.1101/2020.11.01.20222315Google Scholar
Ismai  SA , Saliba  V , Lopez Bernal  J , Ramsay  ME , Ladhani  S .  SARS-CoV-2 Infection and Transmission in Educational Settings: Cross-Sectional Analysis of Clusters and Outbreaks in England. London.   Lancet Infect Dis. 2020;21(3):344-353. doi:10.1016/S1473-3099(20)30882-3Google ScholarCrossref
If you are not a JN Learning subscriber, you can either:
Subscribe to JN Learning for one year
Buy this activity
If you are not a JN Learning subscriber, you can either:
Subscribe to JN Learning for one year
Buy this activity
With a personal account, you can:
  • Access free activities and track your credits
  • Personalize content alerts
  • Customize your interests
  • Fully personalize your learning experience
Education Center Collection Sign In Modal Right

Name Your Search

Save Search
With a personal account, you can:
  • Track your credits
  • Personalize content alerts
  • Customize your interests
  • Fully personalize your learning experience

Lookup An Activity



My Saved Searches

You currently have no searches saved.

With a personal account, you can:
  • Access free activities and track your credits
  • Personalize content alerts
  • Customize your interests
  • Fully personalize your learning experience
Education Center Collection Sign In Modal Right