Health

At-Home Coronavirus Testing Might Be Too Good to Be True

“There's a tremendous amount of wishful thinking in COVID-19 right now. People want to come up with a magic pill, and want to come up with a magic test.”
May 28, 2020, 7:49pm
At-Home Coronavirus Testing Might Be Too Good to Be True
Getty Images/Paul Thuysbaert

Everlywell, a Shark Tank–featured health and wellness startup based in Austin, Texas, jumped the gun on self testing for COVID-19 in mid-March, when it claimed it would be offering at-home test kits for $135 a pop. At that point, the United States had only had a little more than 7,000 lab-confirmed cases of coronavirus, and states were struggling to ramp up testing. Home testing felt like a warranted, albeit capitalist, answer to a mounting lack of test availability—a simple and relatively affordable way to take strain off the healthcare system and let anyone who had the cash gain peace of mind.

The FDA shut down the operation (as well as similar kits from other direct-to-consumer companies) within a matter of days, and warned consumers against “unauthorized fraudulent COVID-19 test kits.” But on May 16, the FDA gave Everlywell’s COVID-19 Home Collection Kit an emergency use authorization (EUA), making it the first such test to carry an FDA stamp at all.

The startup is already accepting bulk order requests from organizations that can “distribute and facilitate testing in a clinical setting,” meaning tests would, theoretically, be at least observed by a healthcare provider. It also has a waitlist going for individual consumers, who can begin buying kits at the end of the month to perform on themselves.

The FDA’s approval of Everlywell’s home test comes on the heels of two other related emergency use authorizations: One for a LabCorp nasal swab self test and another for home collection of saliva samples. Amazon also reported to 60 Minutes in early May that it is aiming to set up self-testing stations for its warehouse employees as they enter their workplaces, rather than employ medical professionals to administer them.

As the U.S. continues to struggle with active infection testing, and the promise of serology (antibody) tests wears thinner and thinner, the ability to self-test for active coronavirus infections becomes more appealing, as an option for reopening the country and sending people back into offices. Privately manufactured, self-collected specimen kits that can be used at home—rather than in a crowded emergency room or urgent care—are a hopeful solution. Yet there are myriad reasons why self-collected samples aren’t as accurate at capturing infection as we’d like to believe, according to Sheldon Campbell, associate professor of Laboratory Medicine at Yale School of Medicine.

“There's a tremendous amount of wishful thinking in COVID-19 right now,” Campbell told VICE. “People want to come up with a magic pill, and want to come up with a magic test.”

As Campbell told VICE, the current, physician-administered test uses a nasopharyngeal swab to reach the respiratory mucosa, or an area so far back in the face that some patients say it feels like the swab is stabbing their brain. The newly approved Everlywell test, on the other hand, instructs people to stick the included test swab just 2–4 centimeters into their nose, collecting an entirely different specimen than the deeper swabs. The LabCorp test collects cells from an even shallower point in the nose, and the saliva test collects, well, spit—all specimens that are understudied with regard to detecting the coronavirus.“The jury is very much out as to whether other specimens are as good as the nasopharyngeal swab,” Campbell said.

He explained that the existing handful of studies examining the use of saliva and mid-nasal swabs, and published in journals including the British Dental Journal and Clinical Infectious Diseases, are riddled with issues of publication bias. “People are much more likely to present positive stories than negative ones,” Campbell said. “So if I did a study and that study showed that saliva was just as good as an nasopharyngeal swab, I'd publish it. But if I do a study that says saliva sucks, I might not publish it, because I can't do anything with that information, and so we move on.” Researchers are both less likely to submit negative results and journals are less likely to publish them, even if they’re extremely important to science. Simply put, a positive study that reveals new, useful information is actionable; a negative study, that disproves a hypothesis, Campbell said, is comparably dead-on-arrival.

Expecting individuals to simply use the reliable, time-tested nasopharyngeal swabs on themselves is unlikely; it’s hard enough to teach physicians to perform the tests properly, much less ask a regular person to stick a swab that far up their own nose. So other specimen types, like saliva and mid-nasal cells, seem like a better option for self-administered and self-collected tests, in that they’re likely to be properly executed. The problem is that they will only ever be as useful as the cells they’re capturing.

Self-collected samples are better than nothing, if you’re OK with a potentially gaping margin of error. “Going back to the era when diagnostic tests weren’t as good: If you have a [hypothetical] 80 percent chance of finding it, that’s better than zero,” he said. “But you’ve got to be careful with better than nothing.”

At a certain point, with enough compromise on “better than nothing,” an accessible, at-home test is only slightly better than useless, and is even actively dangerous if it gives people a false sense of security. It could give rise to a scenario where there are mysteriously very few positive cases, yet many people are somehow getting sick and dying.

The data supporting Everlywell’s emergency use authorization is privately funded research, supported by the Bill and Melinda Gates Foundation and UnitedHealth group. The FDA says this data is now “freely available to support other EUA requests, alleviating each test developer of the burden of recreating the same study. In other words, it’s alleviating startups of the burden of a key tenet of science: repetition.

Between May and March, or in the two months that it took the FDA to change its mind about home-collected, mid-nasal testing, Campbell said it’s possible that the FDA has simply had more time to look into home testing and put more faith into it. “Maybe Everlywell submitted more data,” he added. “I hope so, because what they submitted last time was pathetic.”

Campbell said you’d have to be a “very sophisticated consumer” to know how good the at-home test you’re getting is. Even if the best home-testing kit is 90 percent as good as the (already imperfect) provider-administered tests, how much should a person gamble on those odds? The odds are in your favor, but being the one in 10 could have deadly consequences.

The coronavirus conversation is quickly shifting to risk assessment, something that’s far more complicated than most of us would like to believe. If a swab you’ve stuck up your nose at home and mailed in to an unidentified (but CLIA-certified) lab via FedEx shows a negative result for COVID-19, at least as of three days ago when you posted it, can you really be confident it’s OK to get on a plane or visit someone in a nursing home? And that’s assuming a mere 10 percent margin of error; in reality, we have no idea what the accuracy of these at-home tests is.

Successfully testing oneself for a virus at home isn’t impossible; self-collected specimens have been used in home testing for STIs for years, with the support of dozens of studies. A 2015 review of 21 studies looked at the accuracy of self-collected urine samples versus physician-collected samples for detecting chlamydia and gonorrhea. The review found that self-collected samples recorded a correct positive between 87 and 92 percent of the time, and a correct negative 99 percent of the time. Those are relatively successful rates, even without taking into account the findings of other studies on self-collected STI tests, which show that people are much more likely to get tested promptly and regularly if they can do so in the privacy of their home.

But we’ve known how to accurately and effectively test for STIs for years, with plenty of time to study the results of at-home versions. That isn’t the case for coronavirus; comparatively, we’ve been learning about and developing testing for this virus for almost no time at all. Expecting the same degree of effectiveness, just because the concept of at-home testing exists already, for a brand-new illness isn’t in line with what science can actually pull off.

“People who are working from home already and trying to self-isolate; what are you doing with the result?” Campbell said. “I don’t know that we want people just randomly testing themselves. It’s better to do in the context of your healthcare, and potentially with employers and going back to work, but in a systematic fashion, rather than just, Well I think I need to be tested today.”

With more data and time, it’s possible that home testing will be proven to be comparably reliable to physician-administered tests, but Campbell can’t foresee a reality in which they’re on equal footing. For now, they remain a questionably useful novelty; for $135, you can find out if you maybe had coronavirus a few days ago. Whether you want to bet a trip to grandma’s house on those odds is unfortunately your call.

Follow Hannah Smothers on Twitter.

This article originally appeared on VICE US.