Rapid tests could ‘drive the epidemic to extinction’

WASHINGTON – Inexpensive coronavirus tests that ordinary Americans can administer at home, without a prescription or medical expertise, could dramatically reduce infection rates, researchers at the University of Colorado and Harvard say. Their findings contradict long-standing concerns that rapid tests are less accurate than those sent to labs.

These inaccuracies effectively become inconsequential if enough rapid tests are performed with sufficient frequency, their statistical models indicate.

“The critical conclusion from our work is that when it comes to screening for COVID tests, turnaround time is absolutely critical,” said Daniel Larremore, a computer scientist in Colorado. “It’s because to stop transmission, you have to tell people that they are infected early, so that they can protect the people around them.”

Another of the study’s authors, Harvard epidemiologist Michael Mina, told a Boston-area radio station that if “we could have 10-20 million of these tests every day across America, that would be enough to stop the epidemics across the United States. States ”in just a few weeks, without the need for heavy state and city locks.

This is because these rapid tests would detect many people who may be contagious but who are not really sick. About 30 percent of people show no signs of the virus, but are still able to spread it, potentially disgusting or killing others. These people may never see the need to wait in a long line for a long tampon to be injected into the nasal cavity. But they could eventually be persuaded to apply mucus to a strip of paper in the privacy of a home bathroom.

Some airlines have started offering rapid gate tests to prevent their planes from becoming transmission sites.

The country does not have the capacity to perform rapid tests that supporters of the method deem necessary. The Trump administration has started distributing 150 million rapid BinaxNOW tests. So far, around 63 million of these tests have been shipped either to governors or directly to sites like nursing homes. But a lot more testing would be needed for the type of daily volume envisioned by Mina.

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The administration has invested $ 238 million in rapid antigen testing, according to statistics compiled by the Department of Health and Human Services. Last week, the Food and Drug Administration approved the first rapid test available for home use. The test requires a prescription, and the biomedical company that created it, Lucira, charges $ 50 for each.

“Great first step, but the price of $ 50 worries me,” Advancing Health Equity founder and CEO Dr. Uché Blackstock told Yahoo News.

Harvard epidemiologist Mina is considering rapid tests that cost as little as $ 1.

Rapid tests are also called antigen tests because they look for proteins directly related to the virus. They tend to catch people when they are most contagious, including in the days before symptoms appear. The results only take 15 minutes. Many have compared the whole process of antigen testing (at least in its ideal form) to the type of pregnancy test available at any US drugstore.

Molecular tests (also called PCR tests, for “polymerase chain reaction”) are more precise than antigen tests, but they must be processed in the laboratory. It took up to two weeks. Even now, molecular tests require at least two days of treatment.

For months, researchers preferred molecular testing to antigen testing, emphasizing accuracy over speed. But that’s not the right approach, say the researchers of the new document.

“It turns out that fast turnaround time is actually more valuable than ultra-high sensitivity,” Larremore, a computer scientist at the University of Colorado, told Yahoo News.

Dr Anthony Fauci, the country’s leading voice on the coronavirus pandemic, told Yahoo News that while molecular testing remains the best way to tell if an individual is sick, they are performing broader assessments across the world. community – a concept known as “surveillance testing” – is easier to do with a quick test.

“If you do surveillance multiple times, we know you can make up for a relative lack of exquisite sensitivity in the test,” Fauci told Yahoo News. “And even in tests that are not sensitive, what you might see is that you might be missing someone who is, strictly speaking, positive, but the virus level is so low that it doesn’t will not transmit. “

People can spread the virus before they start showing symptoms. This type of asymptomatic spread has been particularly upsetting to public health officials. It also appears to be precisely the problem that Colorado and Harvard research appears to be addressing.

In one of the models described in the new study, the researchers envisioned a scenario in which 4% of New York’s 8.4 million people tested positive for the coronavirus. This scenario could soon become reality, New York having closed its public schools after reaching 3% positivity on the test, the threshold for such a closure.

Their model was based on the assumption that people wouldn’t stay home for days on end while waiting for test results. At the same time, they would isolate themselves if a test quickly told them they were contagious. “We found that testing 75% of individuals every 3 days was enough to drive the epidemic to extinction within 6 weeks,” the researchers wrote. At that time, the total number of infections would have dropped by 88% compared to a scenario without rapid testing.

Even if only half of the population decided to participate in a rapid screening program, the total number of infections would drop by 58%.

“Delays in reporting lead to significantly less effective control of viral spread,” the authors wrote in their study, which was published in the academic journal Science Advances late last week. Getting results quickly and testing frequently, they say, compensates for inaccuracies in those results. And in a pandemic that kills 1,500 people in the United States every day, waiting several days for slightly more precise results – that is, molecular tests sent to laboratories – is not good health policy public, they say.

“This article is one of the first to show that we should care less about the sensitivity of tests and, in public health, prioritize frequency and turnaround time,” said one of the authors of the study, Colorado biochemist Roy Parker.

It’s unclear how high priority rapid testing is for the inbound Biden administration – transition officials haven’t returned multiple requests for comment from Yahoo News. Biden has said he wants to implement a national testing strategy, but details remain incomplete.

No such strategy has been highlighted by the Trump administration, although the testing situation is much better than it was in the spring. This is still a long way from what public health experts like Mina envision, in part because the president lost interest in the pandemic months ago, but also because the country’s production capacity remains strained.

Earlier this fall, Yahoo News asked Admiral Brett Giroir, the head of the White House coronavirus task force responsible for testing, when rapid coronavirus tests would be available to Americans daily. He dismissed the notion as “utopian”.

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