Medical Examiner

Should Parents Stock Up on At-Home COVID Tests?

An image of an at-home test kit laid out on a blue surface, next to an image of adult hands administering a test to a toddler.
Photo illustration by Slate. Photos by Getty Images Plus.

Gigi Gronvall’s youngest child isn’t vaccinated against COVID-19 yet.

He’s 11-years-old, and until he can receive his shots, Gronvall’s been using at-home COVID-19 test kits in order to determine if his sniffles are more than allergies or a slight cold. The test swabs are longer than a Q-tip, but easier on the nasal cavity than a flu diagnostic or the original “brain swab” used to test for COVID since early in the pandemic.

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“There’s often a lot of stuff coming out of their nose,” Gronvall said of her kids, with a slight chuckle, when we talked recently. As an associate professor at the Johns Hopkins Bloomberg School of Public Health, Gronvall knows the importance of testing. “We can’t all rely on everybody being extra scrupulous and paying attention to all of the COVID restrictions,” she said. And that’s even more true when kids are back in school. “[We] have to do as many things as we can in the school environment so that all the kids are protected.”

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So where do the home tests fit into this back-to-school picture? If used correctly (taken at the right time, in the right way), FDA-approved at-home tests—authorized for kids as young as 2-years-old— can deliver highly accurate results. Some of the FDA-approved kits on the market have an 84 to 95 percent chance of detecting a true positive and 97 to 99 percent of detecting a true negative, according to an analysis by Wirecutter.

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Most of the at-home diagnostic kits for COVID-19 are rapid antigen tests that can be purchased at a local drugstore with or without a prescription. They aren’t a replacement for PCR testing, the CDC-approved gold standard, and anyone who has symptoms of COVID-19 should still seek out a PCR test. But they can be a useful tool to lessen anxiety and COVID spread.

“The tests are … not as sensitive as PCR-based tests,” wrote Christopher Brooke, a virologist at the University of Illinois, over email. “The sensitivity of antigen tests can be increased through serial testing however. If someone takes two or three tests in the week after an exposure and remains negative, that is more convincing than if that person just takes a single test.”

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Gronvall agrees. “Tests are a moment in time,” she told me. “You could be negative and then, a few hours later, you have enough virus in your nose so that if you had taken the test [right then] it would be positive. Nothing is perfect. But these tests are a really good indicator of your contagion risk. If you have enough virus in your nose to make this test turn positive, then you absolutely shouldn’t be around other people.”

I asked Gronvall how she would advise parents to use at-home tests this fall. She suggested using them when concerned that the child is sick, after being potentially exposed to COVID-19, or before seeing an immunocompromised relative—just to be on the safe side.

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A general good rule of thumb is: If a symptomatic user gets a positive result, believe it. If they get a negative, go get a PCR test. If a user is asymptomatic, doesn’t have a known exposure, and gets a negative result, they’re probably fine. If they get a positive, seek out follow-up testing.

“It’s vital that [the at-home tests] are used with your eyes wide open to their limitations,” said Chana Davis, a geneticist who founded the website Fueled by Science and a contributor to the COVID advice site Dear Pandemic. “The way that I think about it is: If the test basically confirms your suspicions, it’s probably right. But if the test doesn’t quite match what you expected, then you need to do some sort of follow-up testing.”

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Davis also cautioned that the tests perform best in someone who has a high viral load. “The tests do tend to perform worse in children, but only because children are more likely to be asymptomatic, thus less likely to have high viral load,” she explained. “When you compare asymptomatic kids and asymptomatic adults, there is not a dramatic difference in performance. The same is true of symptomatic adults versus kids.”

But Davis believes the at-home tests could hold up better against the delta variant since higher viral loads lead to better performance.

“Results will vary from brand to brand, and depending on the user,” she said. “Repeat testing will be the key to getting value from these tests to ‘catch’ the infectious window.” (Efficacy can take a hit when the person collecting the specimen doesn’t use the kit correctly. But Gronvall said YouTube has plenty of thorough demonstrations and even thinks it’s possible for kids to learn to swab themselves.)

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Davis, Brooke, and Gronvall all agreed the tests are a great tool for parents, especially those who don’t feel great about their school system’s mitigation strategies. Still, they emphasized the need for broad safety measures such as masking, proper ventilation inside buildings, and, of course, vaccinations for those eligible.

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“Again, the more frequently parents can screen their kids the better, especially in schools where precautions are not being taken,” wrote Brooke. “That said, these tests cost money and many can’t afford to regularly purchase these tests.”

At-home kits can be found for under $35, and some insurance plans will cover the cost. Aetna pays for all COVID-19 testing for its members, while UnitedHealthcare allows members to use any available HSA/FSA funds to cover the at-home kits. Blue Cross Blue Shield leaves the decision up to the individual states, but many of the state policies I reviewed—including North Carolina, NebraskaGeorgia, and California—only cover COVID-19 tests that are ordered or approved by a healthcare provider.

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But the obvious caveat is: More than 35 million Americans didn’t have health insurance in 2020, and the Urban Institute projects that America’s poverty rate will hit 13.7 percent in 2021. People of color are more likely to fall into both categories, and Black Americans are particularly vulnerable due to America’s racial wealth gap. The pandemic has only exacerbated that divide, which endures across generations and is as calamitous for Black children as for their parents. Early in the pandemic, COVID-19 testing options followed redlines and essentially excluded Black neighborhoods, while the lack of testing in Black communities left a “huge hole” in the data.

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What this means for the at-home testing era is that people who don’t live in an area where free testing is available, or are on a fixed income, won’t be able to protect their families with the same ease as those able to afford the kits. (If you live in D.C., you can grab free at-home kits at libraries across the city, which gives unhoused individuals direct access to routine testing.) So while the at-home tests are a great tool if you can get them, they are certainly not a protective option for all parents. As Shawnita Sealy-Jefferson, a social epidemiologist at Ohio State University, put it: “If the intervention is dependent on flexible resources—like money, power, transportation, and correct information—then they will be useful to people who have those flexible resources and they will not be at all accessible to people who don’t. Then the inequities within whatever the intervention is supposed to address will get worse.” And around and around we go.

Correction, Aug. 18, 2021: This article originally misstated that Blue Cross Blue Shield in North Carolina covered medically unnecessary COVID-19 testing. It covers medically necessary testing.

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