key: cord-0754238-9u9wb9xa
authors: Ciaranello, Andrea; Goehringer, Cathryn; Nelson, Sandra B; Ruark, Liz J; Pollock, Nira R
title: Lessons learned from implementation of SARS-CoV-2 screening in K-12 public schools in Massachusetts
date: 2021-06-04
journal: Open Forum Infect Dis
DOI: 10.1093/ofid/ofab287
sha: 7caed4334c262e0a202f0fada4d5a102b36d6479
doc_id: 754238
cord_uid: 9u9wb9xa

In-person learning provides substantial benefits for K-12 school students. Risk of SARS-CoV-2 infection among educators, staff, students, and household members can be markedly reduced by mitigation measures including masking, ventilation, and hygiene. In addition to these measures, regular SARS-CoV-2 screening testing is recommended by recent CDC guidance and supported financially by ongoing CDC and HHS initiatives for K-12 schools. Screening provides an added layer of risk reduction, as well as data and reassurance about in-school transmission. Financial and logistical constraints have challenged implementation of screening in public schools. We report lessons learned from a collaborative of public K-12 schools implementing and evaluating screening programs, including details of population screened, site of specimen collection, assay selection, pooled testing, and resources needed. This work supported the development of a state-wide screening program and led to dissemination of online technical resources that may support other public schools in implementing CDC guidance.

CDC guidance for K-12 schools emphasizes that screening testing for SARS-CoV-2 -alongside other mitigation measures -facilitates in-person learning while reducing COVID-19 risk among educators, staff, students, and household members. 1,2 We review the definition of screening testing, its potential roles in supporting in-person learning, and lessons learned from pilot public-school programs that may inform implementation in other schools.

Diagnostic testing is used to evaluate symptoms consistent with COVID-19 and identify infection after a confirmed exposure to a person with SARS-CoV-2. Screening testing is testing of individual people without symptoms or known exposure, ideally at regular intervals. Diagnostic and screening testing have distinct and important roles for K-12 schools. Convenient, rapid access to diagnostic testing, with short results turn-around time, should be the first testing-related priority for schools. This is essential to ensure that individuals with infection are identified and isolated quickly and that symptomatic students, educators, and staff without infection can return to school as soon as symptom resolution allows.

CDC advises a layered mitigation approach in schools. Especially where community rates of COVID-19 are high, asymptomatically infected individuals will likely enter school buildings. In-school transmission to others can be effectively prevented by five core mitigation measures: universal correct use of masking, physical distancing (including cohorting), hand hygiene, cleaning and facility maintenance (including adequate ventilation), and contact tracing with appropriate isolation and quarantine. 1,3

Screening testing can add another layer of safety, providing three primary benefits for K-12 schools.

A c c e p t e d M a n u s c r i p t First, screening testing can identify and isolate people with asymptomatic and pre-symptomatic SARS-CoV-2 infection, thereby reducing the risk that people with infection will be present, and thus possibly expose others, in school buildings. Simulation models have estimated that weekly screening may reduce total numbers of infections among educators, staff, students, and household members by up to 90%, depending on time to return test results, grade level, uptake of mitigation measures, and in-person learning schedule (e.g., part-time compared to full-time). 4, 5 Second, repeated screening provides data to assess and guide in-school mitigation strategies. Many studies demonstrating low in-school transmission risk have been limited by testing only people who are identified as in-school contacts; in schools with 6' distancing, few or no in-school contacts may be identified, and not all contacts are tested. Screening of students, educators, and staff will detect possible in-school transmissions quickly, allowing evaluation for breakdowns in mitigation measures and facilitating temporary quarantine and remote learning where needed. 6 At the same time, negative results from uninvolved individuals, classes, or schools can allow in-person learning to continue with confidence. 7 Screening programs can also provide current case-rate data specific to the school community being screened, rather than more generally derived from municipal-, county-, or state-level data. This will be important in assessing the effectiveness of in-school mitigation measures against more transmissible SARS-CoV-2 variants as schools make decisions about in-person learning through the spring and fall of 2021.

Third, screening may provide substantial reassurance to educators, staff, students, and their families. In one public school district, only 12% of educators/staff and 39% of parents were "mostly" or "very" comfortable with in-person learning prior to screening in fall 2020; after screening was implemented, 82% of educators/staff and 87% of parents were "reassured" about in-person learning. 8 Importantly, A c c e p t e d M a n u s c r i p t these second and third benefits (data and reassurance) will remain valuable even if screening programs discover very low rates of infection.

STSS includes approximately 30 public K-12 districts in Massachusetts -serving communities whose racial, economic, and urban/suburban/rural compositions vary widely -working together to implement, evaluate, and support SARS-CoV-2 screening programs. 9 Created in August 2020, the Collaborative's primary goal was to support affordable screening in public schools using the best available technologies, to protect educators, staff, and students and to inform data-driven decisions about in-person learning.

To do this, we advocated for at-cost, broadly available screening methods, in partnership with testing vendors and policymakers; evaluated numerous approaches to screening; shared detailed descriptions of challenges and successes; and disseminated information across the state. STSS meets every two weeks, and member districts submit detailed descriptions of program challenges and successes.

Ultimately, STSS work informed the design of a state-supported program for screening in Massachusetts K-12 public schools, accompanying online implementation resources, and ongoing evaluations of outcomes. 9-12

Population and cadence. If financial and/or staffing limitations require it, schools may decide to test only a subset of people who enter school buildings. We and CDC suggest prioritizing unvaccinated educators and staff, followed by older (high school) and then younger (middle, then elementary) unvaccinated students. Empiric data for specific screening strategies are limited; prioritization has been based on factors including reassurance of educators and staff, prevention of adult-to-adult transmission, likely higher acquisition and transmission risk among older compared to younger students, and simulation A c c e p t e d M a n u s c r i p t models suggesting both higher outbreak risk and larger risk reduction with screening among older students. 4, 5 While most districts do not mandate screening testing, some districts have required screening for participation in voluntary activities, such as athletics and extracurriculars. The optimal screening frequency is also not known; most STSS districts adopted once-weekly screening. Modeling results suggest modest incremental gains from replacing weekly screening with twice-weekly screening. 4, 5 The value of screening of vaccinated educators, staff, and students remains uncertain.

While CDC currently suggests continuation of screening after vaccination, anticipated data about asymptomatic infection and transmission after vaccination, including with emerging SARS-CoV-2 variants, will inform this consideration.

Type of assay and site of collection (Table) . Both polymerase chain reaction (PCR) and rapid antigen assays have been proposed for K-12 school screening. Rapid antigen tests are usually performed on anterior nares (AN) swabs collected on site, while PCR can be performed on AN or saliva samples, collected at school or at home. PCR can be performed on either individual or pooled AN or saliva samples. With pooled testing, specimens from multiple individuals are combined and a single PCR assay performed on the combined "pool;" a negative PCR indicates that all members of the pool test negative.

A positive pool must be "deconvoluted" to provide individual results for each pool member. Ideally, deconvolution can be done using original specimens (e.g., if pooling is performed in the laboratory). If pooling is performed at the school, members of a positive pool require repeat testing, raising important operational and infection-control considerations (Table) . 10 A c c e p t e d M a n u s c r i p t Support, implementation, and community partnerships. Implementation of a K-12 screening program requires substantial financial and staffing resources, the availability of which will differ markedly among districts. 13 In addition to PCR assay costs (ranging from $5 to $50/person screened), STSS superintendents, school nurses, community/parent volunteers, and others have dedicated 0.5-2.5 fulltime-equivalents to implement screening in STSS districts. implemented, both financial and technical assistance for public schools will be needed at the state and federal level. Community outreach has been critical to increase understanding and support for screening A c c e p t e d M a n u s c r i p t among students, families, educators, and staff. Close collaboration with local boards of health is also essential, especially because screening will generate additional contact-tracing and reporting requirements. Prompt and transparent dissemination of results of screening programs, for example on an online dashboard, builds trust among community members and allows screening to serve the purposes of data and reassurance described above. 6 The US Government and CDC have stated their support for in-person learning for K-12 public school students. With careful attention to these key considerations, screening programs can help achieve this vitally important goal.

A c c e p t e d M a n u s c r i p t  Specificity varies by assay; note that even a specificity >98% can lead to a large proportion of positive tests being false positive results, and prompt access to PCR confirmation may be needed.

 Highly specific (most assays report specificity near 100%).  Potential for invalid or inconclusive results with assay inhibition, discrepancy in detection of targets in multiplexed assays, or incorrect submissions (e.g. swab upside down, insufficient saliva volume).  Current assays require schools to obtain CLIA waivers and provide physicians' orders. School-based testing providers also need to obtain PPE, collect samples, process tests, and correctly interpret result readouts. These have been barriers for many schools.

 Depending on testing program or vendor, schools may be required to provide physicians' orders.  PPE and sample collection requirements vary by program design.

Anterior nasal (AN) swab  May be active ("spit") or passive ("drool") collection. Passive collection may take several minutes, particularly in children.  Requires avoidance of food, drink, tobacco, gum before collection.  Can be collected at school or at home (depending on EUA/laboratory validation  Can be collected at school or at home (depending on EUA/laboratory validation data).  Many vendors will permit self-collection by children of varying ages (encouraged by MA program for 2 nd grade and up); can also be performed by parents or school-M a n u s c r i p t data).  Can be used for individual PCR or pooled in the laboratory.

based providers.  Can be used for individual PCR or pooled (with pooling at school or in lab). If samples are physically combined at school, requires members of a positive pool to seek repeat testing (see below).  If re-testing of positive pool members is required, it is possible that all members of a positive pool may have negative followup test results. This may be due to declining viral load between tests (e.g., positive PCR on day 0, negative PCR on day 1-2), and/or may occur with the use of less sensitive antigen tests for deconvolution (e.g., positive PCR on day 0, negative antigen on day 1-2). A clear protocol is needed for repeat testing of members of M a n u s c r i p t the original positive pool in this scenario.

 Individual positive and negative results are reported to health officials.

 Districts will need to work closely with local boards of health to clarify reporting requirements and implications.  Unlike individual screening, people in negative pools are not usually reported to public health authorities as having been tested, and so do not contribute to a community's denominator for the reporting of test positivity rate (although some vendors can do this upon request).  Although jurisdictions in which large-scale asymptomatic screening occurs may wish to separately report results from screening programs and from other testing (e.g., state of MA reports test positivity with and without higher-education screening), this will not be possible with some pooled testing vendors.

M a n u s c r i p t

COVID-19: CDC Guidance for Expanded Screening Testing to Reduce Silent Spread of SARS-CoV-2

COVID-19 Cases and

Passing the Test: A Model-based analysis of safe school-reopening strategies. medRxiv

Model-driven mitigation measures for reopening schools during the COVID-19 pandemic. medRxiv

Medway Public Schools -COVID-19 Information Hub

Wellesley Public Schools. WPS COVID-19 Dashboard. WPS COVID-19 Dashboard

Safer Students: Back-to-School Testing Program Summary

Massachusetts Department of Education. Coronavirus/COVID-19: Pooled Testing in K-12

Safer Teachers, Safer Students Collaborative. COVID-19 Testing Guidance for School Committees: Information and Best Practices for the Efficient and Effective Implementation

COVID-19 Educational Testing. Identifying your Testing Team. COVID 19 Educational Testing

Performance and Implementation Evaluation of the Abbott BinaxNOW Rapid Antigen Test in a High-throughput Drive-through Community Testing Site in Massachusetts

We gratefully thank the members of the Safer Teachers, Safer Students Collaborative and the students, educators, staff, and family members supporting SARS-CoV-2 screening in Massachusetts K-12 public schools. We also thank Alyssa Amick, MPH, for assistance in manuscript preparation.

Between the initial and revised submissions of this manuscript, Dr. Ruark began to work as a paid consultant for the NIH RADx program and for Veritas, a vendor newly participating in the DESE K-12 school screening program; Cathryn Goehringer began to work as a consultant for Veritas and a Massachusetts early education network; and Dr. Pollock was contracted as a subject matter expert for the Massachusetts Department of Public Health.

This work was reviewed and approved as "not human subjects research" by the Mass General Brigham IRB.

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