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The NYTimes on the FDA and Rapid Tests

In July of 2020 I wrote in Frequent, Fast, and Cheap is Better than Sensitive:

A number of firms have developed cheap, paper-strip tests for coronavirus that report results at-home in about 15 minutes but they have yet to be approved for use by the FDA because the FDA appears to be demanding that all tests reach accuracy levels similar to the PCR test. This is another deadly FDA mistake.

…The PCR tests can discover virus at significantly lower concentration levels than the cheap tests but that extra sensitivity doesn’t matter much in practice. Why not? First, at the lowest levels that the PCR test can detect, the person tested probably isn’t infectious. The cheap test is better at telling whether you are infectious than whether you are infected but the former is what we need to know to open schools and workplaces.

It’s great that other people including the NYTimes are now understanding the problem. Here is the excellent David Leonhardt in Where are the Tests?

Other experts are also criticizing the Biden administration for its failure to expand rapid testing. Even as President Biden has followed a Covid policy much better aligned with scientific evidence than Donald Trump’s, Biden has not broken through some of the bureaucratic rigidity that has hampered the U.S. virus response.

In the case of rapid tests, the F.D.A. has loosened its rules somewhat over the past year, allowing the sale of some antigen tests (which often cost about $12 each). But drugstores, Amazon and other sellers have now largely run out of them. I tried to buy rapid tests this weekend and couldn’t find any.

The F.D.A.’s process for approving rapid tests is “onerous” and “inappropriate,” Daniel Oran and Dr. Eric Topol of Scripps Research wrote in Stat News.

For the most part, the F.D.A. still uses the same cumbersome process for approving Covid tests that it uses for high-tech medical devices. To survive that process, the rapid tests must demonstrate that they are nearly as sensitive as P.C.R. tests, which they are not.

But rapid tests do not need to be so sensitive to be effective, experts point out. P.C.R. tests often identify small amounts of the Covid virus in people who had been infected weeks earlier and are no longer contagious. Rapid tests can miss these cases while still identifying about 98 percent of cases in which a person is infectious, according to Dr. Michael Mina, a Harvard epidemiologist who has been advocating for more testing

Identifying anywhere close to 98 percent of infectious cases would sharply curb Covid’s spread. An analysis in the journal Science Advances found that test frequency matters more for reducing Covid cases than test sensitivity.

As I said on twitter what makes the FDA’s failure to approve more rapid antigen tests especially galling is that some of the tests being sold cheaply in Europe are American tests just ones not approved in the United States. If it’s good enough for the Germans it’s good enough for me!

Update on Rapid Tests for COVID

Nearly a year ago, I wrote Frequent, Fast, and Cheap is Better than Sensitive, arguing for rapid antigen tests:

A number of firms have developed cheap, paper-strip tests for coronavirus that report results at-home in about 15 minutes but they have yet to be approved for use by the FDA because the FDA appears to be demanding that all tests reach accuracy levels similar to the PCR test. This is another deadly FDA mistake.

See also my posts Infected versus Infectious and Rapid Tests. The EMA and then the FDA finally did start approving these tests. So how well are they working? Pretty damn well. Canada has two innovative programs. First, in Nova Scotia pop-up clinics have been using rapid tests for asymptomatic people:

During the third wave that hit Nova Scotia over the past month, the province’s community rapid testing centres have correctly sniffed out at least 285 COVID-19 cases in asymptomatic people, or about 10 per cent of all confirmed cases in this time period, according to the Nova Scotia Health Authority.

While most provinces reserve testing only for symptomatic people or close contacts of a case, Nova Scotia’s pop-up centres allow asymptomatic people to simply show up and get a rapid test for free, with results sent to them within an hour. The whole process relies largely on volunteers without a health-care background.

Furthermore, the true number of cases credited to rapid testing is probably much higher. When a rapid test correctly identifies a positive case, the person’s close contacts such as their family get PCR lab tests that don’t show up in the rapid test statistics.

Lisa Barrett, an infectious diseases specialist and the driving force behind the rapid testing program, said it’s hard to say for certain, but taken altogether it’s possible rapid antigen testing has helped Nova Scotia find up to 18 per cent of all cases during the third wave.

“This is the early detection system,” Barrett said. Rapid testing tends to catch people early on in their infection when they’re full of virus, meaning positive cases are found and put into isolation fast — likely days before they would have been found with a PCR test, if they were found at all.

Michael Mina argues that since the rapid antigen detected cases are among the most infectious cases, detecting these cases is probably worth half of all the PCR testing.

Second, Canada’s CDL Rapid Screening Consortium is now in 200 sites with 50 large companies and rapidly expanding. A very interesting, just published paper in The Lancet runs an experiment that suggests that these testing regimes can work. The experiment rapidly tested 1000 people and the negatives were then randomly assigned either to be sent-home to conduct their regular life or to attend a multi-hour concert with masks but also singing, dancing, alcohol and no-social distancing. After 8 days there were two infections in the at-home group and no infections in the Concert group which suggests that this type of rapid testing can be used to open and keep-open concerts, schools, universities, airplanes and workplaces.

What’s the point of testing now that we have vaccines? Two reasons. First, most of the world still hasn’t been vaccinated so testing will be a very useful stop-gap measure until vaccination is more widely distributed. Indeed, the success of these programs shows what we lost by not acting more quickly a year ago. Second, although the pandemic is (essentially) over in the United States (as predicted) there will likely be an uptick in the fall among the unvaccinated and you want rapid tests to be available rapidly in hot-spots. In other words, rapid deployment of rapid tests will help us to avoid outbreaks in the future.

The problem with rapid testing was always on the demand side

The U.S. government distributed millions of fast-acting tests for diagnosing coronavirus infections at the end of last year to help tamp down outbreaks in nursing homes and prisons and allow schools to reopen.

But some states haven’t used many of the tests, due to logistical hurdles and accuracy concerns, squandering a valuable tool for managing the pandemic. The first batches, shipped to states in September, are approaching their six-month expiration dates.

At least 32 million of the 142 million BinaxNOW rapid Covid-19 tests distributed by the U.S. government to states starting last year weren’t used as of early February, according to a Wall Street Journal review of their inventories…

“The demand has just not been there,” said Myra Kunas, Minnesota’s interim public health lab director.

…the tests are piling up in many states, the Journal found.

Here is more from Brianna Abbott and Sarah Krouse at the WSJ.  You may recall the discussions of demand-side issues from my CWTs with Paul Romer and Glen Weyl.  The envelope theorem remains underrated.

Rapid Tests

Here’s a good picture illustrating the difference between the PCR and Rapid Test. A PCR amplifies DNA and so if taken at the right time it will detect the virus before a rapid test will. But this happens when there isn’t much viral load and too little of the virus to be transmissible. Moreover, at these times, the virus is increasing rapidly so the rapid test will find the virus tomorrow. The PCR test will also pick up fragments after transmissiblity has passed which also isn’t very useful. A rapid test is very sensitive for doing what it is supposed to do, identifying periods of infectiousness.

Michael Mina has done a great job promoting rapid tests and I do think we are beginning to see some recognition of the difference between infected versus infectious and the importance of testing for the latter. What is frustrating is how long it has taken to get this point across. Paul Romer made all the key points in March! (Tyler and myself have also been pushing this view for a long time).

In particular, back in March, Paul showed that frequent was much more important than sensitive and he was calling for millions of tests a day. At the time, he was discounted for supposedly not focusing enough on false negatives, even though he showed that false negatives don’t matter very much for infection control. People also claimed that millions of tests a day was impossible (Reagents!, Swabs!, Bottlenecks!) and they weren’t impressed when Paul responded ‘throw some soft drink money at the problem and the market will solve it!’. Paul, however, has turned out be correct. We don’t have these tests yet but it is now clear that there is no technological or economic barrier to millions of tests a day.

Go yell at your member of Congress.

Update on Rapid Antigen Tests

In July of 2020 in Frequent, Fast and Cheap is Better than Sensitive, I wrote:

A number of firms have developed cheap, paper-strip tests for coronavirus that report results at-home in about 15 minutes but they have yet to be approved for use by the FDA because the FDA appears to be demanding that all tests reach accuracy levels similar to the PCR test. This is another deadly FDA mistake.

It’s depressing that we are still moving so slowly on these issues but the media has finally gotten on board. Earlier I mentioned David Leonhardt’s article. Here is Margaret Hartmann in the New York Magazine.

In many Asian and European countries, at-home COVID-19 tests are cheap and easy to find in stores. CBS News reported this month that home antigen tests are now used routinely in the U.K., where they are free and “readily available at pretty much every pharmacy in the country.”

The situation is drastically different here because U.S. health officials focused on getting people vaccinated against COVID-19 and never leaned into asymptomatic testing as a strategy to fight the pandemic. While some foreign governments moved quickly to encourage screening and subsidize the cost of at-home tests, the Food and Drug Administration’s approval process moved much more slowly.

….The FDA said it needed to ensure that the tests were accurate, but many scientists countered that the agency was letting the perfect be the enemy of the good.

Note also that this is a way of saying that the politicians have now also had it with the FDA:

In addition to ramping up production of tests already on the market, the government is also working to speed up the approval process. On October 4, the FDA authorized Flowflex, an at-home antigen test produced by ACON Laboratories that is expected to retail for around $10 per test. And on October 25, the Department of Health and Human Services announced that the FDA will streamline its authorization process, and the National Institutes of Health will spend $70 million on a new program to “establish an accelerated pathway” to aid test makers seeking approval for their products.

FDA Approves American Rapid Antigen Test

I wrote earlier:

What makes the FDAs failure to approve more rapid antigen tests even more galling is that the test being sold cheaply in the Amsterdam supermarket is the Flowflex, an American test made by Acon Labs in San Diego.

Well the FDA has finally approved the Acon test! Apparently it is good enough for the Germans and for US citizens. Hoorah! USA Today notes:

ACON expects to make 100 million tests per month by the end of this year. Production could double to 200 million monthly tests by February, according to the FDA.

…The United Kingdom and Germany have made significant purchases of home tests and widely distributed them to their residents to slow the spread of coronavirus. Such large government purchases allowed manufacturers to continue making tests even when demand softened as cases dropped.

The Biden administration will spend nearly $1.2 billion to purchase up to 187 million home tests from Abbott Laboratories and Celltrion Inc., company officials confirmed. The Department of Defense announced additional contracts totaling $647 million to buy 60 million kits from Abbott and three other testing vendors: OraSure Technologies, Quidel and Intrivio Holdings.

The FDA has authorized seven antigen-based tests that can be used at home without a prescription. The EU has authorized 21 tests beginning with the letter A (I am not sure all of these are authorized for home use but you get the idea.) Turtle slow. Still this is a big improvement.

Frankly, I think all the pressure from people like Michael Mina amplified by myself and others over 18 months and culminating in David Leonhartd’s NYTimes article Where Are the Tests? finally pushed them over the edge.

Rapid Antigen Tests in Canada

Josh Gans announces a program of Rapid Antigen Tests in Canada backed by a consortium of major Canadian companies.

Big News! Today I am very pleased to be able to reveal to the world something that I have been very proud to have been working on with a hundred or so other people: The CDL Rapid Screening Consortium. Led by our Creative Destruction Lab, this consortium is a group of 12 companies who are partnering with Health Canada to begin the roll-out of rapid antigen screens to be a part of daily life for the next 12-18 months and deliver a safer path to normality. We have been working since September intensively to put the consortium together, explore screening options that were available globally and come up with protocols and an evolving standard operating procedure (SOP) to bring rapid antigen screens at scale to economies all around the world. The goal is to solve the pandemic information gap and ensure that we can quickly identify and isolate infectious people and protect others.

The initial sites will be run by RSC members. Those members are Air Canada, Rogers, Loblaws, Shoppers Drug Mart, Magna, Nutrien, Suncor, Genpact, Scotiabank, MDA, CPPIB and MLSE.

Read Josh’s announcement for more details and here is the website for the CDL Rapid Screening Consortium.

Rapid Antigen Tests in Europe

Image‘If rapid antigen tests are so good how come other countries aren’t using them’? is a question I get asked a lot. In fact, India authorized these tests months ago. Slovakia tested most of their population using antigen tests. Germany is using them to protect nursing home residents. Lufthansa is trialing rapid antigen tests on special flights. Rapid antigen tests are now beginning to be available more widely in Europe. Here from a twitter thread is a picture of what they look like, it’s just a paper strip inside. You swab your nose (no need for deep cleaning), swirl the swab in a tube with some liquid and then squeeze a few drops of the liquid onto the end of the tester. Results in 15 minutes. They cost about $8 a test.

Why are these tests important? The CDC now says that asymptomatic or pre-symptomatic people account for a majority of infections. Do you get it? How many people without symptoms will get a COVID PCR test, which can be time consuming and expensive? (And how many PCR tests can we run in a timely fashion if people without symptoms get many more tests?) Not that many. But many people without symptoms would get a $8 or less, at-home, 15 minute test. And if some of those people discover that they are infectious and self-isolate for a few days we can drive infection rates down.

We should have had an Operation Warp Speed for tests. We still need funding for a mass rollout and, of course, the FDA needs to approve these tests! (Here is Michael Mina in Time fulminating at the FDA holdup.)

By the way, more than 2800 Americans have died of COVID since Pfizer requested an Emergency Use Authorization for their vaccine. The FDA meets Dec. 10.

Addendum: Here’s me explaining why Frequent, Fast, and Cheap is Better than Sensitive and the difference between infected and infectious.

Rapid Antigen Tests

Rapid antigen tests are starting to be adopted worldwide.

Reuters: Germany, where infections jumped by 4,122 on Tuesday to 329,453 total, has secured 9 million so-called antigen tests per month that can deliver a result in minutes and cost about 5 euros ($5.90) each. That would, in theory, cover more than 10% of the population.

The United States and Canada are also buying millions of tests, as is Italy, whose recent tender for 5 million tests attracted offers from 35 companies.

Germany’s Robert Koch Institute (RKI) now recommends antigen tests to complement existing molecular PCR tests, which have become the standard for assessing active infections but which have also suffered shortages as the pandemic overwhelmed laboratories and outstripped manufacturers’ production capacity.

See my earlier posts Frequent, Fast, and Cheap is Better than Sensitive, Infected versus Infectious, and Rapid Tests for more on these types of tests.

The problem with rapid Covid testing

Mayank Gupta emails me:

The absolute number of false positives would rise dramatically under slightly inaccurate, broad surveillance testing. At least initially, the number of people going to the doctor to ask what to do would also rise. One can imagine if doctors truly flubbed and didn’t know how to advise patients accurately, a lot of individual patients would lose trust in the medical system (testing, doctors, or both). The consequence of this would be more resistance to health public policy measures in the future.

I see this as quite similar to what happened on three mile island. There was a clear utilitarian benefit to taking on some small amount of nuclear accident risk. The public was never taught how or why to internalize and cope with this risk. When the risk manifested, individuals saw the risk but not the public benefit and turned against nuclear. This change of public opinion was reflected in public policy after.

I’m sure there’s some mismatches in this analogy, but I’m using it to point out that in general I find thinking on the margin without thinking about the public’s ability to think on the margin can result in setbacks on the margin.

In an age where science is both more capable of solving social problems and more complex to understand, but the public has too much complex information to sort through, the central problem of governance seems to be how to solve public choice, without creating a monopoly on information.

To be clear, I do favor rapid testing, but it is worth giving this problem further thought.

Two brutal tests — can you pass them?

We all give people “tests” when we meet them, whether we are consciously aware of it or not.  Here are two of mine:

1. The chess test.  When I played chess in my youth, I would commonly analyze games with other players.  You would then rapidly learn just how much and how quickly the other player could figure out the position and see imaginative variations.  Some players maybe had equal or even inferior results to mine (I had a good work ethic and took no drugs), but it was obvious they were greater talents at analysis.  Top chess players who worked with Bobby Fischer also attest that in this regard he was tops, not just “another great player.”  That was true even before he was good enough and steady enough to become world champion.

When talking ideas with people, the same issue surfaces — just how quickly and how imaginatively do they grasp what is going on?  You should put aside whatever they have or have not accomplished.  How much do they have this Bobby Fischer-like capacity to analyze?  No matter what their recent results have been (remember how Efim Geller used to kick Fischer’s butt in actual games?).

2. The art test.  Take a person’s favorite genres of art, music, whatever.  But something outside of their work lives.  Maybe it can even be sports.  How deeply do they understand the said subject matter?  At what kind of level can they talk about it or enjoy it or maybe even practice it?

Remember in Hamlet, how Hamlet puts on a play right before the King’s eyes, to see how the King reacts to “art”?

Here we are testing for sensibility more than any kind of rigorous analysis, though the analysis test may kick in as well.  Just how deep is the person’s deepest sensibility?

If you are investing in talent, you probably would prefer someone really good at one of these tests over someone who is “pretty good” at both of them.

3. All other tests.

Now, people can be very successful while failing both “the chess test” and “the art test.”  In fact, most successful people fail both of these tests.  Still, their kinds of success will be circumscribed.  They are more likely to be hard-working, super-sharp, and accomplished, perhaps charismatic as well, while lacking depth and imaginative faculty in their work.

Nonetheless they will be super-focused on being successful.

I call this the success test.

Now if someone can pass the chess test, the art test, and the success test with flying colors…there are such people!

And if the person doesn’t pass any of those tests, they still might be just fine, but there will be a definite upper cap on their performance.

Why Doesn’t the United States Have Test Abundance?!

We have vaccine abundance in the United States but not test abundance. Germany has test abundance. Tests are easily available at the supermarket or the corner store and they are cheap, five tests for 3.75 euro or less than a dollar each. Billiger! In Great Britain you can get a 14 pack for free. The Canadians are also distributing packs of tests to small businesses for free to test their employees.

In the United States, the FDA has approved less than a handful of true at-home tests and, partially as a result, they are expensive at $10 to $20 per test, i.e. more than ten times as expensive as in Germany. Germany has approved over 50 of these tests including tests from American firms not approved in the United States. The rapid tests are excellent for identifying infectiousness and they are an important weapon, alongside vaccines, for controlling viral spread and making gatherings safe but you can’t expect people to use them more than a handful of times at $10 per use.

We ought to have testing abundance in the US and not lag behind Germany, the UK and Canada. As usual, I say if it’s good enough for the Germans it’s good enough for me.

Addendum: The excellent Michael Mina continues to bang the drum.

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My Congressional Testimony

I thought the meeting went well. I made four points.

  • It is not too late to do more.
  • We should invest in nasal and oral vaccines.
  • We should vaccinate the world.
  • We should stretch doses through fractional dosing and delaying the second dose, this will be important to vaccinate the world quickly.

One observation. Lots of people are talking about vaccine hesitancy but I am one of the few people who have been talking about nasal and oral vaccines which are the only really solid approach to the issue that I have seen.

My best line:

The unvaccinated are the biggest risk for generating mutations and new variants. You have heard of the South Africa and Brazilian variants, well the best way to protect your constituents from these and other variants is to vaccinate South Africans and Brazilians.

I also got in the last word in Q&A when discussing the pause of J&J:

For the rest of the world it is important to underline that it is most important to get vaccinated now. Use the AstraZeneca vaccine, use the Johnnson & Johnson vaccine…don’t wait for Moderna or Pfizer, it is going to take too long…start your vaccination program early…vaccinate as quickly as possible, that is the route to health and wealth.

See Western Warnings Tarnish Vaccines the World Badly Needs for the beginnings of a disaster. Note that if J&J and AZ are tarnished or knocked out of the vaccine arsenal then dose stretching and investing in more capacity are going to be even more important.

I also submitted five excellent and important pieces to Congress:

Canadian statement on delaying the second dose.

National Advisory Committee on Immunization (NACI) Canada. 2021. “COVID-19 Vaccine Extended Dose Interval for Canadians: NACI Recommendation.” Government of Canada. March 3, 2021. https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/rapid-response-extended-dose-intervals-covid-19-vaccines-early-rollout-population-protection.html.

Value of vaccine capacity and additional investments.

Castillo, Juan Camilo, Amrita Ahuja, Susan Athey, Arthur Baker, Eric Budish, Tasneem Chipty, Rachel Glennerster, et al. 2021. “Market Design to Accelerate COVID-19 Vaccine Supply.” Science, February. https://doi.org/10.1126/science.abg0889.

Efficacy of the first dose from NEJM.

Skowronski, Danuta, and Gaston Serres De. 2021. “Letter to the Editor on Safety and Efficacy of the BNT162b2 MRNA Covid-19 Vaccine.” New England Journal of Medicine, February 17, 2021. https://doi.org/10.1056/NEJMc2036242.

Overview of dose stretching policies (with links in the online version).

Tabarrok, Alex. 2021. “What Are We Waiting For?” Washington Post, February 12, 2021, sec. Outlook. https://www.washingtonpost.com/outlook/2021/02/12/first-doses-vaccine-rules-fda/

A plan to vaccinate the world.

Agarwal, Ruchir, and Tristan Reed. 2021. “How to End the COVID-19 Pandemic by March 2022” SSRN. 2021. https://documents.worldbank.org/en/publication/documents-reports/documentdetail/181611618494084337/how-to-end-the-covid-19-pandemic-by-march-2022

The whole thing is here. My written testimony is here.

Testing and the NFL

NYTimes: The Centers for Disease Control and Prevention and the National Institutes of Health announced a new initiative on Wednesday to help determine whether frequent, widespread use of rapid coronavirus tests slows the spread of the virus.

The program will make rapid at-home antigen tests freely available to every resident of two communities, Pitt County, N.C., and Hamilton County, Tenn., enough for a total of 160,000 people to test themselves for the coronavirus three times a week for a month.

“This effort is precisely what I and others have been calling for nearly a year — widespread, accessible rapid tests to help curb transmission,” said Michael Mina, an epidemiologist at Harvard University who has been a vocal proponent of rapid, at-home testing programs.

I guess this is good news it just feels like something that in a different time line, happened long ago. Here is Derek Thompson in an excellent piece making exactly that point:

Imagine a parallel universe where Americans were tested massively, constantly, without care for cost, while those who tested negative continued more or less about their daily life.

In fact, that parallel universe exists. It’s the National Football League.

..After an October outbreak, the NFL moved to daily testing of all its players and instituted new restrictions on player behavior and stricter rules on ventilation and social distancing. The league also used electronic tracking bracelets to trace close contacts of people who tested positive. Throughout the season, the NFL spent about $100 million on more than 900,000 tests performed on more than 11,000 players and staff members. In January, the CDC published an analysis of the league that concluded, “Daily testing allowed early, albeit not immediate, identification of infection,” enabling the league to play the game safely.

You could write off the NFL’s season as the idiosyncratic achievement of a greedy sport with nearly unlimited resources. But I can think of another self-interested institution with nearly unlimited resources: It’s the government of a country with a $20 trillion economy and full control over its own currency. Unlike the NFL, though, the U.S. never made mass testing its institutional priority.

“The NFL was almost like a Korea within the United States,” Alex Tabarrok told me. “And it’s not just the NFL. Many universities have done a fabulous job, like Cornell. They have followed the Korea example, which is repeated testing of students combined with quick isolation in campus dorms. Mass testing is a policy that works in practice, and it works in theory. It’s crazy to me that we didn’t try it.” Tabarrok said we can’t be sure that a Korean or NFL-style approach to national testing would have guaranteed Korean or NFL-style outcomes. After all, that would have meant averting about 500,000 deaths. Rather, he said, comprehensive early testing was our best shot at reducing deaths and getting back to normal faster.

New CRISPR-based COVID-19 test uses smartphone cameras to spot virus RNA

This one brings us closer to the Star Trek medical universe:

Scientists at UC Berkeley and Gladstone Institutes have developed a new CRISPR-based COVID-19 diagnostic test that, with the help of a smartphone camera, can provide a positive or negative result in 15 to 30 minutes. Unlike many other tests that are available, this test also gives an estimate of viral load, or the number of virus particles in a sample, which can help doctors monitor the progression of a COVID-19 infection and estimate how contagious a patient might be.

“Monitoring the course of a patient’s infection could help health care professionals estimate the stage of infection and predict, in real time, how long is likely needed for recovery and how long the individual should quarantine,” said Daniel Fletcher, a professor of bioengineering at Berkeley and one of the leaders of the study…

The new diagnostic test takes advantage of the CRISPR Cas13 protein, which directly binds and cleaves RNA segments. This eliminates the DNA conversion and amplification steps and greatly reduces the time needed to complete the analysis.

“One reason we’re excited about CRISPR-based diagnostics is the potential for quick, accurate results at the point of need,” [Jennifer] Doudna said. “This is especially helpful in places with limited access to testing or when frequent, rapid testing is needed. It could eliminate a lot of the bottlenecks we’ve seen with COVID-19.”

In the test, CRISPR Cas13 proteins are “programmed” to recognize segments of SARS-CoV-2 viral RNA and then combined with a probe that becomes fluorescent when cleaved. When the Cas13 proteins are activated by the viral RNA, they start to cleave the fluorescent probe. With the help of a handheld device, the resulting fluorescence can be measured by the smartphone camera. The rate at which the fluorescence becomes brighter is related to the number of virus particles in the sample.

And:

Now that the CRISPR-based assay has been developed for SARS-CoV-2, it could be modified to detect RNA segments of other viral diseases, like the common cold, influenza or even human immunodeficiency virus. The team is currently working to package the test into a device that could be made available at clinics and other point-of-care settings and that one day could even be used in the home.

“The eventual goal is to have a personal device, like a mobile phone, that is able to detect a range of different viral infections and quickly determine whether you have a common cold or SARS-Cov-2 or influenza,” Fletcher said. “That possibility now exists, and further collaboration between engineers, biologists and clinicians is needed to make that a reality.”

I recall once asking Silvana Konermann: “What am I going to buy at the CRISPR store?”  Well, this is what you are going to buy at the CRISPR store.

Here is the article.  And funded by Fast Grants, I am happy to say.  Quite the week for science, yes?