Daily coronavirus testing at home? Many experts are skeptical

Over the past few weeks, Harvard scientists have made headlines for a bold idea to prevent the spread of coronavirus: testing technology to bring so-called under-dodge antigen tests, a decades-old one, to millions of Americans nearby – daily, at home.

These tests are not very good at selecting low-level infections. But it is cheap, convenient and fast, will give back the result in minutes. Dr .. Michael Meena argued that, in real-time information, the test pipeline would be much better than long delays.

The rapid and frequent approach to testing has attracted the attention of scientists and journalists around the world. High officials In the Department of Health and Human Services.

Dr. Meena said, often adequately and extensively deployed, rapid tests “can really squash the virus.” “I think it’s crazy not to come back.”

But more than a dozen experts say the ubiquitous ubiquitous antigen test, while interesting in theory, will not fly in practice – and is unlikely to cause an epidemic. In addition to tackling Herculean logistical hurdles, they said the plan relies on the country’s extensive procurement and compliance, which is increasingly fraught with people testing the virus. And they are assuming that fast tests can achieve exactly their intended purpose.

“We’re moving forward with new ways to control this epidemic,” said Asher Babadi, director of clinical microbiology services at the Memorial Sloan Kettering Cancer Center in New York. But antigen tests that can work at home have not yet entered the market.

And no one has done a hard study yet to show Trump’s sensitive-but-slow incoming fast and frequent in the real world, she said: “The data for him is missing.”

Although rapid and frequent testing can work, what has been put forward so far about the approach is “mostly ambitious, and we need to test it against reality,” said Dr. Alex McNander, director of the Infectious Diseases Diagnostic Laboratory in Boston. Said Dam Dam Day. Children’s Hospital Spital, who recently co-authored an article on epidemiological testing strategies in the journal Cl Cl Clinical Microbiology.

While most coronavirus tests performed so far rely on a laboratory technique called PCR, the gold standard for infectious disease diagnosis has long been considered because it can select even very small amounts of genetic material from microorganisms such as coronavirus.

But efforts to collect, ship and process samples for PCR through the sputtering supply chain have been hampered by delays in driving in turnaround times. The longer the wait, the less use it will have. PCR is also not cheap or user friendly, so it makes it an unlikely candidate for widespread home use.

“The home arena is shining with antigen tests,” Dr. Meena said. In their simplicity, they can act very much like a pregnancy test, analyze body fluids and cut the result in a few minutes, no health workers or fancy machines required.

As Dr. Meena saw, these tests can be made from cheap materials like cardboard and sent to communities across the country like rations. They will act as bouncers at the entrances to schools or workplaces, and allow Americans to check themselves at home for coronavirus several times a week, even everyday.

But to achieve that reality will require antigen testing that is not yet valid for widespread use, and the structural features for the construction of the structure. Only four antigen tests have so far received emergency approval from the Food and Drug Administration, and are intended to be used by health care workers on people who have recently shown symptoms. It all also relies on swabs to collect test samples, and all three require somewhat huge and expensive machines to read the results.

“We don’t have tests ready to occupy this space right now,” Dr. McAdam said.

There are other rapid tests in the development of some companies. But there is no guarantee that the newcomers will meet FDA standards. And the last few months have clearly shown that no test is invulnerable to scarcity.

“There’s no reason to believe that the supply chain issues we’ve encountered with all the other coronavirus testing will still not be an issue here,” said April Abbott, director of microbiology at Decons Health Systems in Indiana. “We can’t build new product lines overnight.”

Experts have also noted that antigen tests are not great at extracting small amounts of coronavirus, which means they are more likely to miss a case if they catch a technology like PCR. Some antigen tests detect only half the infection they see. While some new products perform better in the lab, the accuracy rates announced when used at home are almost certainly declining, said Lenoz Samuel, a medical microbiologist at Henry Ford Health Systems in Michigan.

(Some have argued that PCR can actually be very sensitive in some settings, which removes debris of innocent coronavirus genetic material in patients who have not been sick for a long time; antigen testing prevents this.)

Dr. Meena argues that quality can be overcome with decreasing quantity: closer daily tests will be able to detect the transition faster than the backlog PCR pipeline, which will help people to self-isolate in the journey of time. From a public health perspective, the most important thing to people is that they find people at the peak of the infection – something that even antigen tests should be able to do with a high level of accuracy, he said.

But researchers don’t yet know how much virus a person needs to have in their body to become infected – that amount varies from one person to another. And inevitably the “more virus, more transmission” attitude will be the exceptions.

“We just don’t have any evidence that a negative test result means you’re not infected,” said Susan Butler-Wu, a clinical microbiologist at the University of Southern California’s Cake School of Medicine Medicine. Some antigen tests have failed to include high levels of coronavirus in 18% of cases indicated by PCR.

The opposite issue, false positives, is rare with antigen tests, but it does happen. In July, Manchester, v. In dozens of officers tested positive antigen, there was a bracket for the possibility of an outbreak. And in August Gust, Ohio Governor Mike Dewey tested positive for coronavirus by antigen test, only to be tested negative three times in a row by PCR.

In areas where the virus has only infected a few people, the number of false positives can outweigh the number of true positives.

Dr. Mc. “It’s a bad idea to conduct extensive testing with incomplete specialization in areas where there is a shortage of the virus, and I would die on that hill,” said McDam.

Amanda Harrington, director of the Clinical Microbiology Laboratory at Loyola University Medical Center in Illinois, said that with the constant confusion about the flow of new coronavirus tests, high rates of inaccurate results could accelerate public skepticism in science. Said Amanda Herrington.

In the last six months alone, coronavirus tests have been billed as an alternative game changer and a national embarrassment, creating a sense of permanent whiplash among testing specialists.

“My own family tells me I’m not sure what they believe.” Dr. Said Herrington. “You’re misleading confidence to the point where people don’t trust it.”

And a nation of people wary of tests, they will be less likely to take them regularly even if they are available at home.

Uma Karmarkar, a human behavior expert at the University of California, San Diego, said it was possible that adherence to a quick and frequent approach would be less. She pointed to the example of daily medications, such as birth control pills, as well as spotty use of masks.

“Even when there’s an interest, there’s a slippery slope,” he said. With daily testing, even cheaper products can add larger bills, for more dispersal use. (Dr. Meena said the federal government should step up the bill to avoid this issue.)

Dr. Karmarkar said that a satellite of the people can still enthusiastically adopt a fast and frequent approach. But it can be a narrow area of ​​the population, as it can exacerbate the already inclined people to trust the medical system and the epidemiological health inequalities.

Until more data is gathered to support a faster and more frequent approach, Dr. Samuel said. Samuel proposed a temporary middle ground. Schools, universities and workplaces may be good candidates for regular antigen testing, for example, while hospitals and other medical care settings will still prefer PCR.

“The whole idea is that it’s right for the right patient to use the right test at the right time.”

D Min. Meena agreed, noting that PCR remains crucial for the diagnosis of sick patients – a condition that calls for a very sensitive test, so appropriate treatment can be given.

Still, he is optimistic that a quick and frequent strategy could create a major rift in the nation’s coronavirus destruction. That should be encouraging enough, he said: “I really believe people will want to use these tests.”