In August 2020, the school superintendent in Omaha, Neb., approached a microbiology lab at the local university’s medical center. School districts across the country were starting to design pilot programs for routine COVID-19 testing in the coming fall semester, and Omaha Public Schools wanted to join the trend.
The result? During Omaha’s pilot of frequent, asymptomatic testing, the rate of cases detected in the school testing program was six times as high as the case rate reported by traditional testing for symptomatic students only. The pilot program detected 70 cases per 1,000 students, compared with 12 per 1,000 in the official tally reported by the local public health department, researchers report September 22 in JAMA Network Open.
“Asymptomatic screening dramatically increases case detection among students and staff in the K through 12 setting,” says M. Jana Broadhurst, a microbiologist at the University of Nebraska Medical Center who led the team that designed and implemented pilot programs for the school district. In other words, regular testing of all students and staff will catch far more COVID-19 cases than simply testing those who demonstrate COVID-19 symptoms or have a known exposure to the virus. Catching those cases is crucial to nipping outbreaks in the bud and keeping kids in school and healthy.
But this fall, Omaha Public Schools does not have a COVID-19 testing program at all. Why? “The absence of public health guidance on how to utilize and act upon those test results,” Broadhurst says.
Omaha isn’t alone. Throughout the United States, numerous K–12 schools have struggled to implement routine COVID-19 testing, despite expansive funding from the federal government and a recent surge in cases, fueled by the delta variant (SN: 7/30/21). This surge has taken a huge toll on children, demonstrating for many experts the need for deploying testing as a safety measure (SN: 9/20/21). Many school districts have seen more cases among students — and more shut-down classrooms — in fall of 2021 than they did last fall, before vaccines were widely available.
But major hurdles to testing include a lack of clear guidance on how testing programs should work, obtaining tests, gaining consent from parents and communicating the value of testing to families and staff in increasingly polarized environments.
Putting testing to the test
In the last year, both real-world testing pilots like Omaha’s and simulations of different testing scenarios have shown that by routinely testing students and staff, school leaders can identify cases and quickly pull infected people out of the classroom, preventing widespread outbreaks.
“Testing has been widely used at institutions ranging from colleges and universities to the NBA,” says Alyssa Bilinski, a biostatistician at Brown University School of Public Health in Providence, R.I. Testing programs “find people who are currently infectious and isolate them so they don’t spread COVID-19 further.”
At the same time, Bilinski says, testing can provide school leaders with valuable insight into coronavirus transmission in the classroom — information that can inform decisions about increasing or pulling back on other safety measures (SN: 8/9/21).
“Routine testing really has the potential to greatly reduce within-school COVID-19 transmission, and in some cases, even completely eliminate it,” agrees Divya Vohra, an epidemiologist at Mathematica, a research organization with headquarters in Princeton, N.J., who studies testing pilot programs. “We think that it really is a very powerful tool when you layer it on top of all of the other mitigation strategies that schools are implementing, like masking and distancing.”
According to computer simulations, routine COVID-19 testing may reduce in-school virus transmission by up to 100 percent. In the left scenario, the community around this school is facing high case rates (200 cases per 100,000 residents in the last week), while in the right scenario, the community is facing low case rates (25 cases per 100,000 residents). Pooled testing, in which an entire classroom is PCR-tested at once, is the most successful at reducing transmission. Serial antigen testing (antigen tests two days in a row) is more successful than single antigen testing if community cases are high. All scenarios assume that 100 percent of students and staff at the school participate in testing.
Some testing strategies can reduce in-school coronavirus transmission by 100 percent, Vohra and colleagues reported July 26 in a study posted on Mathematica’s website. Pool testing, a method in which samples from an entire classroom are combined and PCR-tested together, is particularly effective at cutting down on transmission when case numbers in the community around the school are high, the models of testing scenarios suggest. This testing method is highly accurate, because PCR tests identify coronavirus DNA in samples, and it provides results more quickly than if each student’s test was processed one by one.
“You’re more likely to catch an infection that an antigen test might miss,” Vohra says. Antigen tests detect proteins on the surface of the coronavirus; they provide results in just 15 minutes and are easy to administer in a school setting. While these tests are less accurate than PCR tests, they are almost as capable of reducing transmission when used once a week or more, especially when community transmission is lower, Vohra says. Testing is most effective when all students and staff are routinely swabbed, but programs may still identify cases when just a subset of the school population is included.
Despite the value of routine COVID-19 testing in schools, any school administrator aiming to test their students faces numerous challenges. Setting up such a program is “like taking the whole entire school on a field trip to somewhere that nobody’s ever been,” says Leah Perkinson, a lead coordinator of K–12 testing pilot programs run by New York City–based nonprofit Rockefeller Foundation.
The first test, she says, is the most difficult. To make that test happen, school leaders have numerous decisions to make. They have to determine which testing strategy to use — PCR or pooled PCR or antigen; nasal swabs or saliva tests — and then procure enough of those tests for hundreds of students and staff. They need to determine who will conduct the tests, when and where testing will occur, how to report test results and how to collect consent from students’ parents and guardians. And, crucially, school officials need to determine what will happen when a test result is positive: Who needs to quarantine and for how long?
Many of these decisions are, in essence, public health decisions — yet school leaders are not trained in public health. As a result, schools need “coordination and support coming from experts, particularly at the state and federal level” to set up routine testing, Vohra says.
Like numerous other aspects of the pandemic, coordination and support for school testing varies greatly across states. Some, including Utah, Delaware, Rhode Island and California, have taken advantage of funding from this past spring’s federal stimulus package to buy tests for their public school districts and provide guidelines on how those tests should be used. But in other places, state-level leaders have refused funding entirely, leaving school districts on their own.
At the federal level, the U.S. Centers for Disease Control and Prevention recommends that schools set up regular COVID-19 testing but offers very limited guidance on specifics. Instead, the agency recommends that school leaders coordinate with their local public health departments.
To fill in the testing information gap for school leaders that lack state guidance, the National Institutes of Health, the Rockefeller Foundation and others have created detailed online resources that let school and public health leaders compare testing strategies and connect with test providers. Still, Perkinson says, these resources may be challenging for school administrators to find and use because the information is “not all in one centralized place.”
Another major challenge that routine school testing programs face, Vohra says, is determining what happens when a student or staff member tests positive. “If you’re identifying more cases, then that’s going to mean that more students are going to be isolating or quarantining,” she says.
Some schools have adjusted their quarantine policies to minimize the number of students missing out on in-person learning. Instead of quarantining an entire classroom, for example, a school may require only those students who sit within six feet of an infected student to quarantine. Policies may also differ for students who are and are not vaccinated. And there is no right answer when it comes to the best strategy, Vohra says.
To help local leaders understand different test and quarantine combinations, Vohra and colleagues built a dashboard based on the results from their modeling study. Users can plug in their testing goals, quarantine policies, community transmission rates and more; the tool offers comparisons of how well different testing strategies fare in reaching those goals.
Another strategy — one not included in the dashboard — is called “test to stay.” Instead of requiring quarantines for students who are exposed to the coronavirus, officials may require those students to get tested at a higher frequency, such as one test a day for a week. A study of secondary schools in the United Kingdom shows that schools where close-contact students were tested daily had similar success in identifying and isolating COVID-19 cases as schools where contacts were all required to isolate immediately. In other words, the “test-to-stay” strategy saved in-person school days while still catching cases, the researchers report September 14 in the Lancet.
In Utah, public schools are required by state law to conduct a “test-to-stay event” when they face an outbreak. In these events, schools host mass testing days; all students must test negative to continue attending classes. A pilot version of the program saved over 100,000 days of in-person instruction for nearly 14,000 students, according to a CDC report published in May 2021 (SN: 8/13/21).
This fall, the program has been implemented statewide but is facing new challenges, says Maggie Graul, an epidemiologist with Utah’s state public health department who manages the program.
The state defines a school outbreak as 2 percent of the student body in large schools or 30 students in small schools testing positive within two weeks — a slightly higher threshold than was used in the pilot program. Schools, public health departments and other local institutions that support “test-to-stay events” are often hesitant to set up mass testing until they hit that outbreak threshold, as they may face community pushback for testing before it is required, Graul says. As a result, she says, the school outbreaks “are actually larger, and we’re not able to contain them as well as last year” during the pilot program.
Opt in versus opt out
A routine school testing program is most effective when all students and staff participate. If testing is voluntary, the families who opt in are likely to be the same families who also follow other COVID-19 precautions, such as wearing masks in public spaces. But schools that institute these programs have struggled with everything from collecting easy-to-misplace consent forms from students to gaining consent in the first place from some parents.
The Rockefeller Foundation’s pilot programs found that, even when families and school staff expressed support for testing in the abstract, it was much harder to get people onboard for a specific testing regimen. For instance, staff opt-in rates at the foundation’s six pilot sites ranged from 25 percent in Tulsa, Okla., to 100 percent in Los Angeles.
Five schools in Los Angeles took part in a pilot COVID-19 testing program. From late March to late May, the schools all together administered over 200 tests a week — peaking at almost 2,000 tests a week in late April. During this time, the overall test positivity rate in these schools (0.01 percent) was much lower than the positivity rate for Los Angeles County (ranging between 0.5 percent and 1 percent). This indicates that coronavirus transmission was lower in the schools that regularly tested their students and staff than in the wider community. (No tests were administered during the week of April 9 during spring break.)
To increase the share of students who get tested, some schools use an opt-out strategy. Rather than students needing a consent form to get tested, they’re automatically enrolled in testing and need a permission form to get out of the program. Baltimore has used this strategy, Perkinson says. New York City also piloted an opt-out strategy in the 2020–2021 school year, requiring all students who attended class in-person to participate in weekly random testing — essentially a participation rate of 100 percent. In fall 2021, however, testing has become opt-in instead of opt-out. Fewer than a quarter of students had opted in as of October 6.
In parts of the country where COVID-19 safety measures in schools have become intensely political, convincing people to opt in can be challenging. Fall 2021 has seen numerous parent protests over these measures — ranging from angry crowds at school PTA meetings to individual families pulling their children out of public schools.
Routine testing programs have not faced the same degree of scrutiny as mask mandates or vaccination requirements. But “testing has been politicized as much as every other aspect of the response to this pandemic,” Broadhurst says. Some of Rockefeller’s pilot programs faced some “families and community members who didn’t really see the value of testing and didn’t really think that schools should be in the business of testing,” Vohra says.
It’s not just politics, either. “Testing can’t happen in a vacuum,” Broadhurst says. If a student tests positive, not only is this student out of school for two weeks, but also a whole family may be out of work in order to quarantine and care for that child, losing crucial income. This creates tension between public health measures and economic security, Broadhurst says. Integrating testing programs with other services —such as free meals and a space to isolate — for socioeconomically vulnerable families may help them agree to participate in testing programs.
Keeping an eye on the goal
Despite the many challenges of routine testing, school leaders and researchers who work on K–12 COVID-19 testing programs are optimistic about this strategy’s potential in the current school year and beyond.
“This is public health; it is not public perfect,” Perkinson says. If a school is not able to meet an ideal testing benchmark for lowering transmission, every individual test is still a win, she says. Every positive result may identify a case before it turns into an outbreak.