CDC Offers Cautions, Guidance for Schools' COVID-19 Testing Strategies
New guidance from the Centers for Disease Control and Prevention gives a framework for school-based testing for COVID-19, detailing who should be tested first and how such screening should be incorporated into schools' overall strategies for controlling the spread of the virus.
It suggests schools prioritize symptomatic individuals and those who've had close contact with those who may be ill with the virus. In a departure from previous CDC guidance, the document also discusses how schools in areas with higher risk of transmission may test broader pools of students and staff as a surveillance tool to monitor the effectiveness of mitigation efforts.
"Schools can help protect students and their families, teachers, staff, and the broader community and slow the spread of COVID-19," it says. "Testing to diagnose COVID-19 is part of a comprehensive strategy and should be used in conjunction with promoting behaviors that reduce spread," like handwashing, regular cleaning of facilities, and the use of face masks.
Officials may want to prioritize testing strategies for schools in high-risk areas, and with large populations of students from disproportionately affected racial and ethnic groups or who lack sufficient access to testing.
The CDC also warns that not every school will have the capability to do testing on site, urging caution about student privacy, data reporting, staff time, and the regulatory clearance necessary to do so.
"The benefits of school-based testing need to be weighed against the costs, inconvenience, and feasibility of such programs to both schools and families," the guidance says, urging schools to work with local health officials and medical providers to plan for off-site testing if it's more practical.
In any case, testing should never be performed without legal consent from adult teachers and staff members or from students' guardians, the agency cautions.
School testing plans are apparently not widespread. In an October survey of educators and administrators by the Education Week Research Center, 16 percent of respondents said their school included testing for employees in their on-site learning precautions, and 7 percent said testing for students was included in their plans.
Schools Using New Rapid COVID-19 Tests
The recommendations come as states receive their first shipments of federally funded rapid Abbott BinaxNow rapid antigen tests, which allow medical professionals to obtain results in 15 minutes without the use of lab equipment. The U.S. Department of Health and Human Services will send 100 million of those tests to states to use at their discretion with the aim of supporting efforts to reopen schools and businesses, federal officials said. We wrote more about that plan in a recent story.
State plans for those tests include incorporating them into existing strategies, using them to test teachers more frequently, and providing them to schools for on-site use. Texas, for example, announced plans Wednesday to pilot rapid testing strategies in eight school districts, the Austin American-Statesman reported.
The CDC recommendations echo cautions from public health officials that rapid tests may not be as accurate as more-traditional tests, which deliver results in two days. But the increased availability of tests makes them a more accessible option for schools, the guidance says.
"Antigen tests usually provide results diagnosing an active [COVID-19] infection faster than molecular tests, but [rapid] antigen tests have a higher chance of missing an active infection even in symptomatic individuals and confirmatory [slower] molecular testing may be recommended," the guidance says. "Although antigen tests have not been authorized for use in asymptomatic individuals, FDA and Centers for Medicare and Medicaid Services have allowed the use of these tests in situations where a rapid result is needed."
Testing to Diagnose Students and Educators
When tracing the spread of an active case of COVID-19, schools should consider three, tiered priority groups, the guidance says:
- People who were less than six feet apart from the person with COVID-19 "for at least 15 minutes or more beginning 2 days before the individual with COVID-19 became symptomatic." School should consider contacts in classes, cafeterias, after-school programs, and athletic or extracurricular events.
- Students and staff in the same "classroom/cohort/pod" as the affected person. This could include students in the same class and students who ride the same bus, even if they weren't within six feet of the person who tested positive.
- People who share a common space, like a teachers' lounge, with the person who tested positive, but were not necessarily in the common area at the same time.
And a negative test result does not negate the need for quarantine, the guidance cautions.
"All persons who are identified as close contacts need to quarantine for 14 days, even if screening test results are negative, because they can still develop COVID-19 for up to 14 days after being exposed," it says. "Quarantine helps prevent spread of disease that can occur before a person knows they are sick or if they are infected with the virus without feeling symptoms. Close contacts who are in quarantine who develop symptoms should be re-tested."
Testing for Surveillance
The CDC previously recommended against broader surveillance testing of seemingly healthy individuals. The new recommendations say schools in areas with moderate to high transmission risk may want to repeatedly screen random samples of students and adults.
New York City has adopted such a strategy, testing more frequently in areas with climbing virus rates. Ashish Jha, dean of the Brown University School of Public Health, recently praised the plan.
Been tweeting about schools today so here's another@NYCSchools doing this right
Random testing to assess how things are going
And if we had ubiquitous testing our federal leaders promised, we could do regular testing of students/staff to stop outbreaks before they start https://t.co/V3Jfals65w
Been tweeting about schools today so here's another@NYCSchools doing this right
"Testing teachers and staff should be prioritized over students in any sampling strategy, and older students prioritized over younger students," the CDC says. "Persons who have recovered from COVID-19 in the past 3 months should be excluded from random selection."
The agency has more caution, however, about the effectiveness of broader, across-the-board, testing strategies that aren't repeated regularly.
"It is not known if testing of all staff, teachers, and students at one point in time (referred to as entry testing or universal one-time testing) provides any additional reduction in virus transmission above the key mitigation strategies recommended for schools," the guidance says. "Currently, CDC does not have specific recommendations for entry testing of all students, teachers, and staff. However, if infrastructure is in place, and resources are available, schools can serve as a venue for health departments to offer community-based testing to teachers, staff, students and potentially their family members."
Many school districts that have incorporated testing into their reopening plans say they see it as part of a multi-pronged strategy along with precautions like social distancing, not as a way of eliminating transmission altogether.
The Pierre, S.D., district is one of about 70 that enrolled in a voluntary state "sentinel testing" program, through which a small, randomly selected portion of its asymptomatic staff are tested weekly. Pierre has about 350 staff members in its schools, and the state provides five tests a week, business manager Darla Mayer said. Since the district started participating in September, just one of those tests has returned with a positive result, and the effective member immediately went home to quarantine, she said.
While testing all staff more regularly may be more effective at keeping the virus out, it would also take a significant amount of staff time and resources, she said. The sentinel program is a tool for the district, but it's most useful at the state level, where officials can track results across school systems over time, Mayer said.
"We've never been through this before, so we're open to learning as much as we can," she said.
Photo: A young child is tested for COVID-19 at a free, walk-up testing clinic in Seattle. Schools around the country are exploring on-site testing or working with local health officials to screen students for potential cases of the virus. (AP Photo/Elaine Thompson)
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