Rapid-result testing on the rise
A wealth of new COVID-19 tests could soon help states more broadly track people in schools, dense workplaces and vulnerable populations.
In October, the supply of rapid-result COVID-19 tests, also known as antigen tests, shot up to more than 150 million – six times the number of tests of any kind performed in August and 10 million more than the total number performed in the United States since the pandemic began, according to the COVID Tracking Project, a volunteer-run organization begun by The Atlantic.
And unlike laboratory-based polymerase chain reaction tests – known as PCR tests – whose numbers can be expanded only in small increments, antigen tests can be produced quickly and cheaply to meet demand.
In theory, the growing supply of rapid-result antigen tests should allow millions of asymptomatic people – who make up at least 40% of those infected with the coronavirus – to be regularly screened for the virus, and for those who test positive to be isolated to curtail spread in classrooms, workplaces and other environments.
But so far, that's not the plan. Instead, most states say they expect to use the 15-minute tests to diagnose symptomatic people in prisons, police and fire departments, health clinics and other places that already are set up to conduct testing. Some states also are making the kits available to school nurses to test anyone who complains of symptoms.
A few states plan to use the new tests to control viral spread in specific highrisk populations.
Public health experts caution against relying too heavily on rapid tests to defeat the pandemic.
“No test is perfect,” said Gigi Gronvall, an immunologist and senior schol
ar at the John Hopkins Center for Health Security.
“Without a plan, without a strategy, more testing isn't going to get us out of this pandemic,” Gronvall said. “Anybody who thought testing was the way out just has to look at the White House to see that if you rely on testing alone, you're going to fail.”
At a Sept. 26 event at the White House to introduce Supreme Court nominee Amy Coney Barrett, more than 200 mostly unmasked attendees sat close to one another, shook hands and hugged in part because frequent antigen testing led them to think they were safe, Gronvall explained. Following the event, President Donald Trump and his wife, Melania, tested positive for the virus, as well as at least nine attendees, part of an outbreak of more than two dozen cases connected to the White House.
Mask wearing, physical distancing, limiting the size of gatherings and holding them outside, along with hand
washing, building ventilation and other measures will still have to be maintained, even if every person in the country gets tested every day, Gronvall said.
In addition, health experts point out that even the most accurate COVID-19 test is only a snapshot in time. People infected with the novel coronavirus can test negative before the virus reaches a level that can be detected and be contagious days or hours later. Alternatively, people can get a negative COVID-19 test result in the afternoon and become infected that evening.
The federal government shipped 100 million credit card-size rapid-result antigen tests to states in October, leaving it up to governors. Made by Abbott and branded Binaxnow, the tests cost $5 and can deliver results in 15 minutes to patients' cellphones.
But despite the exponential rise in COVID-19 testing capacity, some leading public health experts argue the United States still doesn't have enough.