When history looks back on the COVID-19 pandemic, 2020 will likely emerge as the year of testing, while 2021 (and probably 2022) will be the year of vaccinations. But that doesn’t mean testing no longer matters. Testing will become more critical than ever as schools, gyms, workplaces, restaurants, and shops reopen, and sports events and concerts rev up again. Given that reality, the recent availability of at-home DIY tests is welcome news. Last week, Abbott’s BinaxNOW COVID-19 test—which doctors and hospitals have already been using to screen people—became available at retail stores without a prescription.
That’s just in time for the expected departure from lockdown and social isolation this summer. As people start mingling again, they will need access to more convenient, rapid testing that can provide immediate answers—did my child get infected after playing in a soccer game? Did I get infected after going back to work? Is having a family dinner with relatives who don’t live with you safe?
The standard gold testing for SARS-CoV-2, molecular, or PCR, requires people to go to a health care professional, who swabs a sample from deep in the back of the nose and throat and then sends the model to a lab that performs the test. Results take at least a day. But such testing isn’t always necessary. Testing yourself not once but as often as needed to ensure you haven’t been infected from your activities will become the priority in the coming months.
The reason for that has to do with the changing landscape of the pandemic. Last year, when infections were spreading like a fire blazing out of control, testing was essential for identifying positive people so they could isolate and get the proper care. In most cases, doctors focused testing on people who had symptoms of COVID-19, like coughs, fever, chills, and difficulty breathing. If you weren’t feeling sick, there wasn’t a reason to get tested, especially at the beginning of the pandemic when the tests were scarce and took a week or more to produce results,
As more people get vaccinated, however, theoretically, fewer people will be infected, and even fewer will have symptoms. Instead of an inferno, the infections will be more like embers, scattered in communities here and there and harder to find. That’s where home, or DIY testing, like Abbott’s kit, comes in. These are tests that people can buy at their local pharmacy without a prescription, perform independently without any medical help, and get results in about 15 minutes.
The U.S. Food and Drug Administration (FDA) has now authorized four such at-home over-the-counter COVID-19 tests: two from Abbott (the BinaxNow, as well as the BinaxNow Ag Card, which allows people to collect the sample and perform the test while connected to a telehealth provider (an option for those who want the guidance of a professional), and one each from Quidel and Illume. People swab their noses—not the back of the nose and throat that the other test requires—and place the sample in a specially treated card or tube that provides results similar to a pregnancy test in 15 minutes.
They are all antigen-based tests, meaning they pick up proteins made by the SARS-CoV-2 virus and not the virus itself. But the level of viral proteins is a proxy for how active and infectious the virus is. SARS-CoV-2 is busiest in the first week after infecting a new host, pumping out more and more copies of itself. That’s when people are most likely to pass the virus on to others through coughs, sneezes, or other close contact, even if they don’t feel any symptoms. And those are the exact people these antigen tests are designed to find.
How at-home antigen tests can slow the pandemic
“These tests aren’t just to tell you if you are sick,” says Dr. Michael Mina, assistant professor of epidemiology at Harvard T. H. Chan School of Public Health. “These tests are society’s way of seeing the enemy around us; in this case, the enemy happens to be a virus. If you can’t see it, you don’t know what precautions to take.” Because they don’t require a prescription, and anyone can take the tests, Mina says their availability should vastly increase access to testing, which should, in turn, help limit the spread of the virus.
Parents worry about whether their child’s cough and fever are due to a cold or COVID-19 can use the test at home, for example, and if it’s positive, get in touch with a pediatrician—all without having to bring their sick child into the doctor’s office and potentially infect more people. People attending small gatherings, or taking a trip, can test themselves beforehand and afterward, so they can be reassured that they haven’t been infected. And schools can rely on the tests to screen for and isolate positive students or staff and trace any potentially exposed contacts as quickly as possible.
Mina says that such democratized testing should have been the foundation for the COVID-19 response from the start. Instead, since the first test for SARS-CoV-2, from the U.S. Centers for Disease Control (CDC), was slow to roll out after problems arose with its accuracy, and regulatory agencies like the FDA were initially hesitant to allow commercial and academic tests on the market, health officials have been blindfolded in trying to fight the virus. “Instead of testing extensively, the whole pandemic, we treated everyone like they were positive,” says Mina, “and we had to shut the whole of society down because we’ve been blind.”
The at-home tests could finally give us the eyes we’ve needed into the virus’ comings and goings—and help avoid another blanket shutdown. In Maryland, the health department is piloting programs to use at-home rapid testing to identify cases among high-risk populations such as home care health workers and people with disabilities. “We’re trying to target folks who can’t afford to get tested but can benefit from having them,” says Jonathan Weinstein, director of COVID-19 testing passports for the department. Weinstein also sees the self-tests as a way to expand the reach of testing by making them available at places like schools, festivals, and baseball stadiums.
How public health officials can make at-home testing even more useful?
However, one barrier to the widespread use of self-tests is concern about their accuracy since health professionals won’t be involved in collecting the samples or interpreting the results. That’s why some experts don’t see them as powerful public health tools, although they might be useful for individuals making personal decisions. “There are lots of conundrums for public health that we are trying to work through,” says Kris Ehresmann, director of infectious disease epidemiology, prevention, and control at the Minnesota health department. “I don’t want to suggest that they have no utility. From a public health system and data collection perspective, and how we make our broader recommendations, I think there are enough gaps in validation and quality of the results that we must be careful.”
She notes that self-tests are a good starting point to identify new cases, but using them to take broader action is still problematic. If, for example, a student on a school soccer team tests positive using an at-home self-test, is that enough to quarantine the rest of the group, who might have been exposed to that player, and pull the entire team from upcoming games? She says to make those kinds of decisions, “You want to make sure you feel confident about the test’s sensitivity and specificity. There will be a lot of learning in the next months and years until we ultimately reach a place where we can speak more confidently about the role and place these tests will have.”
Those decisions will also depend on the balance between the test’s sensitivity in detecting infections and its convenience and accessibility. A CDC study of Abbott’s tests (both use the same chemistry) was conducted at community health centers in November and December of 2020 compared to the results of PCR tests. They found that the Abbott test picked up 64% of cases among people with symptoms but only 35% among those without. Because symptoms usually occur within days of infection, Abbott says its test is useful for identifying most infectious people and, therefore, could help identify infected people early and ultimately ccontrolthe spread of disease.
Mina points out that the use case for at-home testing differs from that of molecular or PCR testing. At-home testing, he says, is better suited to screening a population for infections, where the more involved PCR test isn’t always necessary or practical. And for much of the pandemic’s beginning, the FDA only allowed PCR testing, even if it meant people waited as long as ten days for the results. That strategy slowed the availability of at-home testing in the U.S.; they are only now becoming widely available just over a year after the first case was confirmed when they could have been useful all along in giving public health officials a better sense of where patients were before they became clusters. “We want everything to be controlled and perfect, even if it is at the expense of testing failing,” he says. “We would rather not have any test than an imperfect test, which doesn’t make sense.”
The goal of testing is also changing from one that is entirely focused on public health needs to one that is increasingly personal and individual. “If you are asking if you can see grandma right now, you’re asking if you are infectious right now. And that’s what the quick at-home tests allow,” says Mina. “The super-high-sensitivity PCR tests are effectively finding if someone was infectious two or three weeks ago, and that’s not the information you want about whether it’s safe to visit your grandma right now.”
“Public health is all about dealing with messy data,” he adds, about the potential that some results may not be as accurate as PCR testing. “We can look for signals in the noise.” One way to do that is to repeat the antigen at-home tests to have more confidence in the result. Indeed, Abbott’s BinaxNOW kit has two tests so users can do just that. Mina does acknowledge, however, that the at-home tests could become more useful for public health purposes if they include a way for people to easily report the results to their local health authorities so the data can be collected more systematically. “We should be linking the tests to simple one-click reporting that should be anonymous and only geolocates by your zip code,” he says. “If we have more testing, then even if a small fraction of people are reporting, ultimately that would provide more public health data, not less. Not having that reporting option is a big mistake.”
The FDA appears to be leaning toward encouraging at-home testing, which could become a huge missed opportunity. The agency has also authorized two at-home, over-the-counter PCR tests from Lucira and Cue, which are more than 90% accurate in replicating results from lab-based PCR tests—and ready in 20- to 30 minutes rather than a day or so. Eventually, people may use the cheaper antigen tests, which run $20 to $30, on a more regular basis, and if they test positive, spring for the $50-plus at-home PCR tests to confirm the result.
As more people take advantage of self-testing, it’s up to the CDC to take advantage of new funding for COVID-19 surveillance to find ways to tap into and exploit that data as more people engage in social activities and want to reassure themselves that they’re doing so safely. Mina says most tests are still not cheap enough to reach everyone wishing to use them—but it’s a start. “Self-tests are a powerful tool at your disposal if and when we need it,” he says.
