This Briefing Note was completed by the Evidence Synthesis Unit (Research, Analysis and Evaluation Branch, Ministry of Health) in collaboration with a member of the COVID-19 Evidence Synthesis Network. Please refer to the Methods section for further information.
This note summarize the evidence on COVID-19 testing strategies for children and staff in schools.
*The full version of the Briefing Note including the Appendix can be accessed in the PDF file at the top of the page*
- A living rapid review (Mar 19, 2021) noted that while surveillance reports are identifying COVID-19 cases among staff, students, and children in schools and daycares, these commonly include single cases or a small number of cases typically less than five. A growing number of studies have randomly selected schools/classes/individuals to undergo testing for active infection (via RT-PCR) or antibodies; consistent across studies, few additional cases are detected, suggesting that widespread asymptomatic transmission is not commonly occurring in these settings.
- US and Canadian guidance generally recommends molecular tests for students and staff, with saliva/nasal samples, sample pooling, or rapid tests as options for more accessible and faster testing approaches. Community prevalence should guide testing frequency (e.g., once per week in areas of moderate-to-high community transmission).
- School testing strategies were identified from Winnipeg, Montreal, Saskatchewan, the US (e.g., Los Angeles, New York City, Massachusetts), England, and Berlin (Germany).
- Administration: Strategies are implemented via collaborations within government, industry, hospitals, and/or research institutions. Testing teams include trained health care providers, support staff, or existing staff resources, with options for supervised self-administration.
- Frequency: Testing ranges from weekly to twice-weekly with options for pooled or random sampling, and results are obtained within 15 minutes to 72 hours.
- Test Type: Molecular PCR (nasal swab or saliva) or rapid tests, with the latter option most commonly used.
- Settings: Testing is primarily conducted in K-12 schools, but other locations may include childcare centres, homes, community test centres, and mobile teams.
- Population Targets: Primarily students, teachers, and other staff, but a few strategies only target staff or include parents/guardians/household bubbles of students participating in school-based learning.
- Outcomes: The Rockefeller Foundation’s COVID-19 Antigen Testing pilot program in six US states was the only initiative identified that reported outcomes on the first four months of planning and implementing rapid testing programs in K-12 schools. Weekly screening of all students and staff was found to reduce in-school infections by 50%, making it more effective than masking but less effective than social distancing. However, less frequent or widespread testing added limited value above and beyond other mitigation strategies. In communities that already have a robust testing program, schools should consider whether they need a school-based program or if they could encourage students and teachers to have regular testing at existing community sites.
Guidance (Jan 21, 2021) from The Hospital for Sick Children and Unity Health Toronto recommends that robust testing and contact tracing of students alongside other infection prevention and control measures (e.g., screening, physical distancing) be implemented in order to resume in-person learning and keep schools open even when community transmission is high.
School testing strategies should be driven by the local context, including testing capacity, community prevalence, and vaccination status of students and staff. Screening and surveillance protocols should be piloted to test the feasibility, impact, and rapid scaling of such testing. Alongside testing, existing preventative practices should continue in schools (e.g., symptom screening, hand washing, masks, physical distancing, ventilation). Cost, access, logistics burden, and lag time in receiving test results may be key barriers to testing strategies.
This section below summarizes scientific evidence and jurisdictional best practices on COVID-19 testing strategies for children and staff in schools, including information on age groups, frequency, type(s) of tests, settings, and administration.
School Testing Studies
- A living rapid review of 89 publications by the National Collaborating Centre for Methods and Tools (Mar 19, 2021) noted that there is a growing body of reports using national or regional surveillance data and comprehensive contact tracing and testing strategies to minimize the likelihood of underestimation of COVID-19 cases in schools. While surveillance reports are identifying cases among staff, students, and children in schools and daycares, these commonly include single cases or a small number of cases, typically less than five.
- A growing number of studies have randomly selected schools/classes/individuals to undergo testing for active infection (via RT-PCR) or antibodies; consistent across studies, few additional cases are detected suggesting that widespread asymptomatic transmission is not commonly occurring in these settings.
- The use of more rigorous data collection (e.g., random testing, comprehensive contact tracing/testing) and enhanced reporting of surveillance data (e.g., index cases, secondary transmission, overall prevalence) in future studies can provide more robust data for interpretation and improve the certainty of findings.
- The DETECT Schools Study (Feb 22, 2021) is a prospective observational cohort surveillance study investigating the incidence, transmission, and impact of SARS-CoV-2 in 79 public schools across Western Australia. There are three modules: 1) random spot-testing of 150 students and staff per month for three to six months to screen for asymptomatic SARS-CoV-2in 40 schools; 2) enhanced surveillance of close contacts following the identification of any COVID-19 case to determine the secondary attack rate of SARS-CoV-2in 40 schools; and 3) survey monitoring of school staff, students, and their parents to assess psycho-social wellbeing following the first wave of the COVID-19 pandemic in all 79 schools. Modules 1 and 3 are in progress, and Module 2 will be initiated as needed.
- A combined oropharyngeal and anterior nasal (OP/Na) swab will be used, and PCR testing of all swabs for SARS-CoV-2 will be carried out using an in-house PCR platform. Testing team members are trained in swab collection by a pediatric infectious disease specialist, as well as the use of the data collection database.
- This protocol is the product of an effective partnership between multiple stakeholders, including government, health service providers, researchers, and the community.
School Testing Challenges
- A US research commentary (Dec 3, 2020) noted that available guidance documents typically instruct schools to gain access to testing by contacting local public health departments, and few schools appear to have solidified a strategy, especially one that extends beyond testing of symptomatic persons. Most reopening plans instead focus on screening for COVID-19 symptoms. While the commentary advocates for routine screening using rapid tests, it highlights why it is challenging for schools to implement: 1) access to testing because of financial barriers and K-12 schools are reliant on either public health departments or private contracting; 2) lag time in receiving test results, particularly with limited access to rapid diagnostic tests; and 3) logistics of implementing recommended responses to positive COVID-19 test results (e.g., isolation, quarantine, remote education delivery). These challenges also exacerbate pre-existing socioeconomic and racial inequities among schools. The commentary suggested that the federal government can help by continuing to fund development of novel tests, including rapid antigen and saliva-based tests, and by strengthening efforts to ensure swift, broad, and equitable distribution.
- Guidance was identified from the following US institutions: US Centers for Disease Control and Prevention (CDC)(Dec 4, 2020; Mar 19, 2021), US Department of Education(Feb 12, 2021), and Duke-Margolis Center for Health Policy and Johns Hopkins Center for Health Security (Oct 2020).
- Administration: School administrators should collaborate with public health officials for implementing school-based testing strategies by trained health professionals.
- Frequency: Dependent on the level of community transmission, but at least once per week for screening testing, especially in areas of moderate-to-high community transmission.
- Test Type: Molecular or antigen tests for diagnostic and screening (random samples or pooled testing) purposes.
- Settings: Schools and the community.
- Population Targets: Use a tiered risk approach, for example: 1) symptomatic students, teachers, and staff; 2) close and potential contacts; and 3) asymptomatic individuals with possible exposure in the context of outbreak settings.
- Consent: Should be required.
- Challenges: These may include limited resources and training, high degree of coordination and information exchange, legal issues (e.g., privacy, consent, who administers tests), and efficacy of antigen tests.
- School testing strategies were identified from Los Angeles’ (LA) Safe Steps to Safe Schools program, Massachusetts’ (MA) Pooled Testing program, New York City’s (NYC) initiative, the Rockefeller Foundation’s COVID-19 Antigen Testing pilot program in six US states, England’s asymptomatic testing program, and Berlin’s Testing Strategy.
- Administration: Strategies are implemented via collaborations within government, industry, hospitals, and/or research institutions in all jurisdictions. Testing teams include health care providers and support staff (LA, NYC, and Rockefeller) or existing staff resources (MA), with options for supervised self-administration for teachers and older students (MA and NYC). Self-administered testing kits are provided for home delivery or at community test sites (England).
- Frequency: Weekly pooled testing with results within 24-48 hours (MA), random weekly testing of 20% of school population with results provided within 48-72 hours (NYC), weekly testing (Rockefeller), and twice-weekly testing (England). Routine testing, but no further information provided (LA and Berlin).
- Test Type: PCR-RT nasal swab or saliva tests (LA), swab tests (NYC), and rapid tests (MA, Rockefeller, and England).
- Settings: Tests are conducted in K-12 schools (LA, MA, NYC, and Rockefeller), childcare centres (England and Berlin), homes or local community test centres (England), and community test centres and mobile teams at schools (Berlin). Individuals can also get tested by their own care provider (LA).
- Population Targets: Students, teachers, and staff in all jurisdictions, and parents, guardians, or household bubbles of students participating in school-based learning (LA and England). There are options to target smaller subsets of schools, grades, students, or staff (MA).
- Consent: Consent is required (LA, MA, NYC, and Rockefeller), and those who do not wish to participate must continue online learning (LA, MA, and NYC).
- Outcomes: The Rockefeller Foundation’s pilot program was the only initiative identified that reported outcomes on the six sites’ first four months of planning and implementing rapid point-of-care antigen testing programs in K-12 schools. Weekly screening of all students, teachers, and staff was found to reduce in-school infections by 50%, making it more effective than masking but less effective than social distancing. However, less frequent or widespread testing added limited value above and beyond other mitigation strategies. Many teachers, students, and parents felt more comfortable returning to in-person learning if they knew that their school would provide testing. In communities that already have a robust testing program, school leaders should consider whether they need a school-based program or if they could encourage students and teachers to have regular testing at existing community sites.
- Canada’s COVID-19 Testing and Screening Expert Advisory Panel recommended (Mar 12, 2021) testing and screening strategies in primary and secondary schools.
- Administration: Shifting the screening and testing process to other trained individuals (e.g., paramedics, parents, secondary students) may reduce the strain on health care workers.
- Frequency: Community prevalence should guide testing frequency.
- Test Type: PCR tests as screening tests preferably, with swish-and-gargle, spit, or nasal sample collections and sample pooling to provide more accessible testing approaches.
- Settings: Primarily in communities with high prevalence of COVID-19.
- Population Targets: Children, teachers, and staff.
- School testing strategies were identified from Winnipeg’s Fast Pass pilot program, Montreal’s pilot project in two high schools, and Saskatchewan’s Rapid Testing program.
- Administration: Testing strategies are implemented by researchers (Montreal), medical companies (Winnipeg), and government (Saskatchewan). In all jurisdictions, tests are administered by trained individuals.
- Frequency: Testbookings are made through an appointment system with results provided within eight hours (Winnipeg), and asymptomatic volunteers are chosen at random weekly with results available within 15 minutes (Montreal). Testing parameters are to be determined in Saskatchewan.
- Test Type: Rapid tests (Winnipeg, Montreal, and Saskatchewan).
- Settings: Tests are conducted in two high schools (Montreal), a central community location so potentially symptomatic people are not entering schools (Winnipeg), and in all-12 schools (Saskatchewan).
- Population Targets: Only teachers and other staff in schools, childcare centres, family/group childcare homes (Winnipeg), and students, teachers, and staff (Montreal and Saskatchewan).
- Guidance (Jan 21, 2021) from The Hospital for Sick Children and Unity Health Toronto, with contributions and endorsements from other hospitals and providers, recommends that robust testing and contact tracing of students alongside other infection prevention and control measures (e.g., screening, hand hygiene, physical distancing, cleaning) be implemented in order to resume in-person learning and keep schools open even when community transmission is high.
- Administration: Early partnership with schools and testing partners is recommended to minimize organization and logistical burden on schools.
- Frequency: Targeted large-scale, one-time surveillance (i.e., point prevalence) programs for pre-symptomatic or asymptomatic children are not generally recommended, but exceptions may be considered for situations where the pre-test probability of SARS-CoV-2 infection is higher (e.g., moderate-to-high prevalence settings and in schools with outbreaks identified). Routine (e.g., twice-weekly) testing of asymptomatic students prior to entering the school may be considered during periods of moderate-to-high community transmission; however, it is not currently recommended or feasible with the available testing options. This recommendation should be re-evaluated as new tests become available taking into consideration test availability, properties, and testing priorities.
- Test Type: Decisions about which PCR or rapid tests to use should consider test properties and practical aspects, such as sensitivity, specificity, purpose (diagnosis vs. surveillance), ease of collection and processing, and the time required to obtain test results. Laboratory-based molecular tests are preferred for symptomatic or asymptomatic children, given its high sensitivity and capacity. The nasopharyngeal swab is the preferred specimen type, but alternatives (e.g., saliva, buccal-nares swab testing) may be considered as they minimize discomfort, allow for ease of testing, and require less human resources.
- Settings: On-site mobile testing and/or targeted surveillance initiatives are recommended.
The COVID-19 Evidence Synthesis Network is comprised of groups specializing in evidence synthesis and knowledge translation. The group has committed to provide their expertise to provide high-quality, relevant, and timely synthesized research evidence about COVID-19 to inform decision makers as the pandemic continues. The following member of the Network provided evidence synthesis products that were used to develop this Evidence Synthesis Briefing Note:
- McMaster Health Forum
Individual peer-reviewed articles and review articles were identified through PubMed, COVID-19 Evidence Network to support Decision-making (COVID-END), and Google Scholar. Grey literature was identified through Google and relevant government websites. The search was limited to English sources and therefore may not capture the full extent of initiatives in non-English speaking countries. Full-text results extracted were limited to those available through Open Access or studies made available to the Ministry by our partners. There was a limited amount of time available to perform this literature search, and as a result, this Evidence Synthesis Briefing Note may not have captured all of the information available.
The following keywords were used to identify relevant articles and documents for this Evidence Synthesis Briefing Note: “child*”, “COVID-19”, “policy”, “program”, “SARS-CoV-2”, “school”, “strategy”, “teacher”, and “testing”.