Why Rapid Coronavirus Tests in Schools May Not Be the 'Game Changer' Some Officials Hope For
School leaders around the country hope that a federal shipment of easy-to-use, rapid test kits will help them stop the coronavirus from spreading in their buildings—and will keep students and staff members who may otherwise have to quarantine in their classrooms.
To use an Abbott BinaxNow rapid antigen test, a medical professional rubs a swab inside a patient’s nostrils and then onto a small piece of cardboard the size of a credit card. The tests require no lab equipment and produce results within 15 minutes, much faster than the more accurate and more common COVID-19 tests, which typically produce results in two days.
Some state leaders have hailed the tests as a “game changer” for schools.
But, while the tests can help reduce the risk of transmitting the virus within a building, they can’t eliminate it entirely, epidemiologists warn. States and school districts need clear guidance about how to incorporate testing into their plans for tracing and isolating cases of COVID-19, and they need to continue practices such as mask wearing and social distancing to drive down the chances of transmission between asymptomatic individuals, those experts said.
“It has to be part of an overall strategy,” said Gigi Gronvall, an immunologist and professor at the Johns Hopkins University School of Public Health. “We are not going to be able to test our way out of this pandemic.”
100 Million Tests
Shortly after the Food and Drug Administration granted emergency authorization for the BinaxNow test in September, the U.S. Department of Health and Human Services announced plans to buy 150 million of the test kits–the entire inventory that Abbott will produce for the remainder of the year.
The agency plans to send 100 million of those tests to governors to use at their discretion, “to support efforts to reopen their economies and schools immediately and fast as they can,” President Donald Trump said at a Sept. 28 announcement at the White House. Less than a week later, Trump announced he had tested positive for the virus after the White House strategy, which relied on screening all visitors with a similar rapid test, had failed.
Public health officials say such tests, which were approved to detect the virus in people with symptoms of COVID-19, are an important tool, but they must be used carefully. The rapid tests, which detect viral proteins in the body, are less sensitive than the slower and more common tests, which detect genetic information related to the virus. That means a person who tests negative on the rapid test one day could test positive the next as the viral load grows in their body.
As states prepare for the initial federal shipments of the test kits, governors have announced plans to incorporate them into their existing community testing strategies, significantly boosting their capacity. In some cases, health officials plan to conduct the tests directly in schools.
Mississippi Gov. Tate Reeves, a Republican who attended the White House announcement, said his state will use the new tests to support an existing plan to provide frequent rapid tests to teachers.
“While we have testing available now at least once a week in every county of our state, what this allocation is going to allow for us is we will have testing available for our K-12 teachers every single day going forward,” he said at the event.
Other states plan to use the tests to reduce the churn that occurs when seemingly healthy students and staff are required to quarantine for a few days because they had close contact with a symptomatic classmate. States and school districts have varying quarantine policies, but for many, a lag time in test results can mean a handful of students transition to remote learning for a few days only to return after a symptomatic classmate gets a negative result.
Limiting Quarantine Churn
In Florida, some school nurses have started training to use the test kits after Gov. Ron DeSantis, a Republican, said he would send the initial shipment of 60,000 tests directly to districts.
"This will be for any student or teacher that develops symptoms and needs to be tested," DeSantis said at a news conference. "If a student is either sent to school that's sick or becomes sick in school, you take the student out, isolate them. But then if you can get a 15-minute test and you get the negative, then you don't have to worry about isolating some of these other students."
South Carolina plans a similar strategy, focusing on symptomatic individuals, said Ryan Brown, a spokesperson for the state’s education department.
“It makes people feel a lot more comfortable knowing that if you are symptomatic, you’d be able to go nearby and be tested,” Brown said. “That provides a lot of anxiety relief, particularly for adults in the school building.”
The state’s strategy is similar to one used by the 50,000-student Charleston County district, which recently announced a partnership with a nearby medical school to provide another version of rapid testing onsite for students and school staff.
“It would allow us to do contact tracing immediately, knowing there’s a positive case and identifying close contacts right away," Chief Operating Officer Jeff Borowy told local news station WCSC.
Screening Entire Student Populations
Other districts around the country have previously announced their own plans to use various forms of COVID-19 tests more widely, as a form of surveillance and screening of entire populations of students and employees or of large samples of people who enter school buildings.
Los Angeles Unified, the nation’s second largest district, announced plans in September to gradually test every student, teacher, and staff member, posting positive case counts on a public website and tracing contacts to slow the spread of the virus.
In New York City, the nation’s largest district and the original U.S. epicenter of the coronavirus pandemic, officials are conducting random tests on students monthly. Recently, Gov. Andrew Cuomo, a Democrat, announced plans to increase the frequency of that surveillance to weekly in schools near virus hot spots.
The state has not yet announced how it plans to use its shipment of the new BinaxNow tests or if they will be used in the screening strategy.
Public health experts say that, while the slower PCR tests may be more accurate, the time waiting for test results is a factor that can lead to greater transmission of the virus, especially if individuals don’t take proper precautions while they await results.
While experts agree on the use of rapid tests on symptomatic individuals, they are more divided on using them for broad screening purposes.
In July guidance, the U.S. Centers for Disease Control and Prevention did not recommend universal testing of all students and staff in K-12 schools, regardless of the type of test used.
"Universal SARS-CoV-2 testing of all students and staff in school settings has not been systematically studied," the CDC said. "It is not known if testing in school settings provides any additional reduction in person-to-person transmission of the virus beyond what would be expected with implementation of other infection preventive measures (e.g., social distancing, cloth face covering, hand washing, enhanced cleaning and disinfecting). Therefore, CDC does not recommend universal testing of all students and staff."
CDC Director Robert Redfield said last month the agency planned to offer revised guidance on testing, but it has not released any school-specific recommendations in the time since.
‘Chains of Transmission’
Michael Mina, a Harvard University epidemiologist who has advocated for the expansion of rapid virus testing, said on Twitter after the White House announcement that the number of tests federal officials plan to distribute is "nowhere near what's needed.”
Mina has advocated for a massive expansion of rapid test production, allowing every American to take a test nearly every day. That’s a far greater undertaking than testing every teacher once a week, which White House officials suggested as a use for the new rapid tests.
Time between tests gives greater opportunity for individuals to catch the virus, or for asymptomatic carriers to spread it without knowing they have it.
But the rapid tests provide a useful tool for schools, and for driving down transmission in communities, said Gronvall, the Johns Hopkins immunologist.
That’s because the tests are more likely to catch the virus in people who have higher levels of it, and those people with higher viral load are also more likely to pass the virus on to others, she said.
Thoughtful use of the tests can “cut the chains of transmission” for the virus, giving it fewer chances to spread in a school, she said. But school administrators shouldn’t expect to create a bubble where there is no presence of the virus at all.
That overinflated sense of security seemed to be the mistake some White House staff made, Gronvall said. Trump himself often said he rarely wore a mask because people around him were tested frequently, for example.
So, even as they increase testing, schools need to stick to proven strategies like wearing masks, keeping students in cohorts, and even reverting to remote learning if levels of community transmission surge, she said.
“Testing can’t be the only thing they’re doing because the testing is such a snapshot of that particular time, and you are dealing with the limitation of that particular test,” Gronvall said. “You can’t neglect these other things until we have a vaccine.”
Vol. 40, Issue 10, Pages 6-7Published in Print: October 21, 2020, as Why Rapid Coronavirus Tests in Schools May Not Be the ‘Game Changer’ Some Officials Hope For