COVID-19 diagnostic testing has been greatly scaled up from a few thousand tests per week back in early March to 2 million tests per week in late July. But the summer upsurge in COVID-19 diagnoses, hospitalizations, and deaths in the U.S. highlights the fact that that amount of testing is not providing both individual Americans and health care professionals with enough information to curb the pandemic's spread.
"In many states, it now takes 10-15 days to get test results—rendering these tests useless as a tool to prevent transmission and bring the pandemic under control," notes Harvard medical professor Ashish Jha in Time. A big part of the problem is that most asymptomatic, pre-symptomatic, and mildly afflicted people don't know that they are infected as they spread the virus to others while working, shopping, and gathering in enclosed spaces like bars and restaurants. Researchers believe that people are at their most infectious about two days before they experience any symptoms of the disease.
Making cheap rapid tests available for use at workplaces, schools, and at-home could solve this information deficit problem. "The way forward is not a perfect test, but one offering rapid results," Jha argues.
Last week, the Food and Drug Administration (FDA) issued its template for approving tests that "can be performed entirely at home or in other settings besides a lab, such as offices or schools, and that could be available without a prescription." It's about time. "We hope that with the innovation we've seen in test development, we could see tests that you could buy at a drug store, swab your nose or collect saliva, run the test, and receive results within minutes at home, once these tests become available," said FDA commissioner Stephen Hahn. "These types of tests will be a game-changer in our fight against COVID-19 and will be crucial as the nation looks toward reopening."
According to George Mason University economist Alex Tabarrok, it's way past time for the FDA to take this step. "A cautious, risk-averse FDA with an exponentially growing virus — that is a recipe for disaster, and that is exactly what has happened," Tabarrok said to the Washington Examiner. "The FDA, as usual, following their standard operating procedure, has been very slow, and I think that has impeded testing right from day one."
The good news is that there are a number of companies that are working on and could soon deploy rapid at-home COVID-19 diagnostic tests based on detecting viral antigens. Antigen tests work by detecting the presence of coronavirus proteins using specific antibodies embedded on a test strip coated with nasal swab samples or saliva.
The Cambridge, Massachusetts, biotechnology startup E25Bio is already seeking FDA approval to launch by September 1st its direct antigen rapid tests (DART) for COVID-19. According to a press release, it is designed as a cheap, paper-based test similar to a pregnancy test that can deliver a visual readout of COVID-19 results in 15 minutes or less. The company says that its manufacturers will be able to produce millions of tests per week.
I reported in July that researchers at the Massachusetts Institute of Technology (MIT) and the technology conglomerate 3M announced that they are collaborating to roll out a highly accurate antigen test that delivers results within 10 minutes, also via a paper-based device. The MIT press release notes that "the Covid-19 test would not need to be administered in a medical setting." This suggests that the tests could eventually be sold directly to consumers for at-home diagnoses. Once the test is sufficiently validated, 3M plans "to produce millions of the affordable, accurate tests each day." The researchers think this will be possible by the late summer or early fall.
What at-home antigen tests lack in accuracy compared to lab tests they more than make up for in frequency of testing. Accuracy of diagnosis would be increased by repeated testing that would also identify the higher viral loads during an individual's most infectious period. For example, one simulation published in JAMA Network Open looked at the impact of antigen testing every two days on a 5,000-student college campus. Their model suggested that such screening could limit an outbreak beginning with 10 students to just 28 infections by the end of the semester.
The pandemic is occurring in an open-access health commons in which individuals cannot take full responsibility for spreading disease. Making cheap COVID-19 antigen tests widely available sooner rather than later would provide Americans the information they need to take such responsibility.
Given that in its response to the pandemic that federal government has already borrowed $3 trillion and appears set to borrow trillions more, as I argued earlier, the cost of $15.6 billion to provide 300 million Americans with at-home test kits costing $1 each for weekly use would be a real bargain. Knowing that their fellow citizens are taking responsibility for their microbes would give Americans the confidence to venture out of lockdown and return to work, travel, school, and the pleasures of bars, restaurants, concerts, sporting events, and movies.
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