Comment: As at-home covid test replace PCRs, we need guidance

By Faye Flam / Bloomberg Opinion

Rapid antigen tests have been among the tools many public health experts and politicians have to ease into “living with covid.” But many people are still skeptical about the tests’ reliability.

The bigger problem may be with the advice people are getting on how to use them. It’s never been clear to the public precisely when to test or how to act on the results if you’ve been exposed or feel sick, or whether a negative test can shorten an isolation period for someone who’s been infected. And what counts as an exposure; what if you were with a friend who got a cold but never got tested?

The guidance that comes in the test kits is so confusing that a study published in JAMA showed that it was worse than no enclosed advice at all. The rapid test instructions were fine as far as collecting the sample and reading the results. But the guidance failed at helping people know how to act on their results. Should they quarantine? Test again? Wear a mask – and for how long? Improving that guidance should be a priority with yet another covid wave looming in parts of the U.S. and at-home testing increasingly replacing PCR testing.

The study’s lead author, Seven Woloshin, a professor of medicine at Dartmouth and founder of the Lisa Schwartz Foundation for Truth in Medicine, admitted he was confused by the guidance included with his test. So he and his colleagues found 360 volunteers and randomly assigned them to three groups. Some read the guidance included with the test kits, another got no guidance, and the third got guidance the researchers developed.

Volunteers were asked what “Jamie,” a healthy 45-year-old, should do after testing negative. In one scenario he had no recent exposures and no symptoms, and in others he had either symptoms, a recent exposure, or both. Among those who read the guidance included in the test kits, 36 percent failed to recognize when Jaime should quarantine. Without guidance at all, that fell to 21 percent; so the instructions actually made things worse. When the researchers used guidance they created, the failures fell to 4 percent. Those instructions used a color-coded decision tree to help people sort themselves into four groups depending on whether they had symptoms, recent exposure, neither or both.

The study was done in 2021, on an earlier batch of rapid tests, and the CDC’s recommendations have changed since then. But currently used test kits — including the free ones provided by the Biden Administration — still include only a long, confusing section of fine print on interpreting results: “additional confirmatory testing with a molecular test for negative results may be necessary after second negative result for asymptomatic persons, if there is a high likelihood of SARS-CoV-2 infection, such as in an individual with as close contact with Covid-19 or with suspected exposure to Covid-19 or to communities with high prevalence of infection. …”

That’s why it’s important to test public health guidance, said Baruch Fischoff, a Carnegie Mellon University expert on risk communication and a co-author of the study. “You will discover that there are things you thought were clear, that they thought were unclear … or that others interpret completely differently than the way you did,” he said. “There are things that they needed to know, that you thought went without saying.”

Advocates for home testing have long argued they should be used to routinely screen people who are regularly exposed to lots of others; in nursing homes, schools or other settings. The tests aren’t accurate enough to catch every single case, but widespread testing would catch most cases and help keep overall case numbers lower. Tests could also be used to make a small gathering safer by capturing at least some of the potentially infectious guests beforehand. But the tests are not the “get-out-of-jail free” card people understandably want and they don’t replace the need for other layers of protection; like vaccination and ventilation. Even so, they’re a tool we could be using more effectively to fight covid.

Woloshin and his late partner Lisa Schwartz had been longtime champions of a more consumer-friendly culture in health care. They’ve advocated, for example, that if the FDA is going to allow misleading, manipulative pharmaceutical advertisements, it should at least require clear, risk-benefit information on a “Fact Box” similar to the nutrition boxes manufacturers are required to include on packaged food.

Rapid covid testing may never be foolproof, but people can act more responsibly in the face of complexity if they’re given clear instructions and messages. “Throughout my whole career people will say, ‘What are you doing? It’s a waste of time … Patients are too stupid to understand stuff,’” Woloshen said. “And I think that’s just horrible because people are smart.”

It’s been a recurring impulse throughout the pandemic to blame people for being dumb or selfish when guidance has in fact been senseless or poorly communicated. If we’re going to “live with covid,” we need to stop expecting people to follow public health guidelines that are so complicated even doctors have trouble understanding them.

Faye Flam is a Bloomberg Opinion columnist and host of the podcast “Follow the Science.” She has written for the Economist, the New York Times, the Washington Post, Psychology Today, Science and other publications.