Alex Tabarrok, Anti-Vaxers, Coronavirus, COVID Screening, Covid-19, E25Bio, Emergency Use Authorization, False Positive, Falze Negative, FDA, Harvard, Infectious vs Infected, John Cochrane, National Basketball Players Association, NBA, Paper Tests, Rapid Tests, Regulatory Failure, SalivaDirect, Self-Quarantine, Test Accuracy, Tracing, Transmission Chain, Vaccine Development, Vaccine Supply Chain, Wyss Institute for Biologically Inspired Engineering, Yale, Zach Lowe
Most of the news about COVID vaccine development is positive, but there are still huge doubts about 1) whether an effective vaccine(s) will ever be available; 2) when it will be available; 3) in what quantities (supply chains for vaccines present issues that most lay persons would never imagine) ; 4) the best approaches to allocation across young/healthy vs. old/vulnerable; 5) how long it will provide protection (the news is good on lasting immunity as well); and 6) whether people will actually take it. Given all these uncertainties, it’s worth considering an approach to stanching the coronavirus that won’t require a vaccine while still allowing a return to normalcy: cheap, rapid tests available to consumers on a daily basis in their homes or in businesses.
The full benefits of cheap, rapid tests can take people a while to wrap their heads around. In fact, there are skeptics who’s views on any and all testing are colored by suspicions that increased testing is some sort of conspiracy to spread fear and keep the economy hobbled. It’s true that increased testing drove much of the increase in COVID cases this summer, which caused the mainstream media to delight in spinning alarmist narratives. Fair enough, but that misses the point, which I’ll try to elucidate below. I credit a John Cochrane post for bringing this to my attention.
A successful vaccine breaks the so-called “transmission chain”, but so does frequent testing to identify infectious individuals on an ongoing basis so they can self-quarantine. As Alex Tabarrok has emphasized, we should worry about identifying infectious individuals, as opposed to infected individuals. They are not the same. Cheap, rapid, and easy-to-administer tests have already proven to be fairly accurate during the infectious stage. The idea is for individuals to self-test every day and stay home if they are positive. Or, employers can test workers every day and send them home if they are positive. Frequent testing also makes it simpler to trace the source of an infection and may reduce the importance of tracing.
To those who say this represents an affront to personal liberty, and I’m very touchy on that subject myself, recall that even now people are being screened in their workplaces using thermometers, questionnaires, or on the basis of any frogginess perceived by supervisors and co-workers. Those “tests” are far less accurate in identifying COVID-19 contagiousness than the kinds of cheap tests at issue here, and they are certainly no less intrusive. Then there are the many businesses facing restrictions on their operations: how “accurate” is it to keep everyone at home by locking down places of business? How intrusive is that? Those restrictions are indefensible, and especially with the advent and diffusion of cheap, rapid tests.
Of course, people might cheat and not report positives. Tests could be administered at workplaces to avoid that possibility, or at points of admission to businesses and facilities, but a few minutes of delay would be necessary. I would not support a centralized database of daily test results. If nothing else, relying on the good faith of individuals in reporting their results would be a giant leap forward in breaking the transmission chain now, rather than counting on the possibility of a successful virus in the indefinite future. And we might then avoid the whole pro-vax/anti-vax imbroglio that already foments, which raises major questions bearing on individual liberty.
Then there is the question of positive tests within multi-person households. Should the entire family or household self-quarantine? I say no, not if the others are negative, but then the others should test twice before going out, which dramatically reduces the probability of a false negative, and they should probably test more frequently, perhaps several times a day.
There are other important details to address: Who will pay for the tests? Will workers be paid to stay home if they test positive? How long will they be required to stay home? How will repeated tests be treated? I don’t want to get into detail on all of these points, but cheap, fast tests can help overcome many of these difficulties, and I believe many of the details can and should be worked out privately.
Unfortunately, the FDA has approved only two rapid tests, and they are not very rapid and not cheap enough. Only one had been approved up until last weekend because the FDA found the accuracy to be lacking … compared to PCR tests! But the FDA finally issued an Emergency Use Authorization for a saliva-based test (SalivaDirect) developed at Yale, partly funded by the NBA and the Players Association. The test still requires processing at a lab, so it’s really not convenient enough and not fast enough. Here is Zach Lowe on the cost:
“The cost per sample could be as low as about $4, though the cost to consumers will likely be higher than that — perhaps around $15 or $20 in some cases, according to expert sources.”
Not bad, but it’s much higher than more rapid, paper tests developed by Harvard’s Wyss Institute for Biologically Inspired Engineering and a company called E25Bio. Both of those are expected to cost about $1 per sample and can be completed anywhere. That’s a price that can work. And there are other promising candidates.
The benefits of tests that are rough, ready, and cheap will be huge. Such tests will also enable retesting, which helps to overcome the dilemmas of false positives and negatives. False negatives might be of greater concern to the FDA, but again, false negatives are less likely during the contagious stage of an infection, and the tests will be accurate enough that transmission risk will be drastically reduced.
The FDA needs to move beyond its stodgy insistence on achieving laboratory levels of accuracy. It’s unlikely that a single test source will be adequate to stanch the transmission chain, so the agency should rush to approve as many cheap, rapid tests as possible, with as many advisories and patient warnings regarding test results and follow-up instructions as it deems necessary. Remember, these tests are much better than thermometers!
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