Story at a glance
- Rapid tests could be as affordable as $1 per test, allowing people to get tested more frequently.
- The tests would not be used for diagnosing COVID-19 but for surveillance of a community to identify potentially infectious individuals.
- The FDA has not approved a rapid test for emergency use as of yet.
Rapid tests are typically low-cost tests with quick turnaround; it can give you a result in around 10 to 15 minutes, similar to an at-home pregnancy test. Researchers have developed rapid tests for the coronavirus, but why aren’t they being used?
What is a rapid test
Often, rapid tests take the form of strips of paper you dip into a tube of saliva mixed with chemicals. The strip then changes color to indicate a result. The tests can be done at home or at the entrance to a building.
These are not the same as antibody tests or rapid antibody tests, which look for proteins produced by the immune system to bind to foreign particles like viruses and indicate that someone may have been infected before but not currently.
To create a rapid test for the coronavirus, researchers target a segment of the ribonucleic acid (RNA) genetic sequence for SARS-CoV-2 or proteins on the surface of the virus called antigens. Tests provide a one-time result that can be thought of as a snapshot of infectiousness.
im well aware. but a test is just a snapshot of that moment in time. so that wouldve shown the prevalence of covid last week -- if kids cant get access to rapid tests going forward, then it will be challenging to prevent outbreak.— Steph McKay, MPH (@stephmckay1) August 13, 2020
While a rapid test is not as sensitive as polymerase chain reaction (PCR) tests, it is sensitive enough to detect infection in many cases. It’s a good measure of infectiousness, or the period of time when someone has enough virus to be able to spread it around. Some PCR tests may be too sensitive, detecting viral RNA fragments rather than the whole virus.
“The vast majority of PCR positive tests we currently collect in this country are actually finding people long after they have ceased to be infectious,” says Michael Mina, who is an epidemiologist at Harvard Medical School and the Harvard T.H. Chan School of Public Health, to Harvard Magazine.
A rapid test for the coronavirus could make reopening safer and increase the size of permitted crowds. If there was a SARS-CoV-2 rapid test approved and available, that means we could do more frequent testing for essential workers and people returning to work and school. Experts have said that a rapid test could cost as little as $1 per test, which greatly opens up the possibilities for testing more frequently.
What are the barriers?
Researchers have developed rapid tests for the coronavirus. They exist.
The Federal Drug Administration (FDA) has given approval for several tests and treatments for emergency use. This is a special designation that means while the test or drug is not officially approved by the FDA, it is approved specifically for use during the pandemic because it is an emergency situation.
The agency released a template for how developers of rapid tests could get their tests approved. However, the FDA has not yet approved the emergency use of a rapid test. It did approve the emergency use of tabletop machine ID NOW and delivers 7 million of their tests weekly to all 50 states, Washington DC, Puerto Rico and the Pacific Islands, according to correspondence from the company. However, the FDA later warned about accuracy concerns.
Another barrier is making sure that if rapid tests are deployed, they are used appropriately. Although they may be easy to use, it’s important not to take them out of context. Rapid tests are not intended to be used for diagnosing COVID-19; they are meant to surveil a population, meaning to keep track of any potential cases in a group of people. If a rapid test comes back positive, then that person would need to go for further testing to find out whether they really are infected with the coronavirus.
What are the experts saying?
Some preliminary work by Mina and collaborators suggests that testing frequency is more important for surveillance than test sensitivity. Several experts have expressed support for more widespread use of rapid tests.
The point is... they exist. They work. We need them to be mass produced to be useful to break transmission. It’s not a difficult or even particularly risky concept - unlike waiting for a vaccine.— Michael Mina (@michaelmina_lab) August 11, 2020
A must-watch video on #RapidTestsNow with E25Bio Co-Founder Dr. Herrera by @MedCramVideos. Fast, cheap, at home tests antigen tests (no machines needed) can crush #COVID19.@michaelmina_lab @j_g_allen @davidboxenhorn @PaulSaxMD @ATabarrok @ScottAdamsSays https://t.co/M04a5zZMdN— David Keating (@DavidLKeating) August 12, 2020
Experts are not saying to replace PCR testing with rapid tests. PCR tests are necessary for diagnosing in a clinical setting, like at the hospital when taking in patients, but rapid tests in the general population could help us get a better sense of how many people are infected at a given time.
“You can’t detect, let alone defeat, an enemy flying blind,” writes economist Laurence Kotlikoff, who has collaborated with Mina, in Forbes. “But that’s exactly what we’re doing relying exclusively on PCR.”
Many experts are saying that the only way out of the pandemic without a vaccine is with frequent testing, tracing and isolation. There are many ways that we can fail at each of these.
Testing may be more accessible now than it was at the beginning of the pandemic, but there are reports of the results not being given to patients for as long as a week or more. Contact tracing is important, but if you don’t have enough staff then you will always be behind and potentially leaving many people exposed. Isolation is not possible for some folks who may live with others or not have any options to self-isolate. In these cases, hotel rooms or other safe places to quarantine could be provided by the government.
PCR-tests can find tiniest remnants of the virus for a long, long time. It's like finding fingerprints and acting like the thief is still in the house! Remember all those scary, sensationalist stories about "re-infections"? Many were likely PCR picking up RNA remnants for months.— zeynep tufekci (@zeynep) August 14, 2020
How soon could we get rapid tests?
The first step towards making rapid tests available is for the FDA to approve the existing ones for emergency use. Health experts should provide guidelines for including rapid tests in a reopening strategy for schools and businesses.
Because the rapid tests are relatively simple compared to PCR tests and don’t require extensive training to administer, they could be easily distributed and put into use once they are manufactured. One company called e25 says it could potentially make 4 million tests a month soon after getting FDA approval and ramp up to 20 to 40 million a month, according to The Atlantic. A few other companies are also working on rapid tests.
Simple cheap fast tests that could be available now/soon and kill the outbreaks at “warpspeed”— Michael Mina (@michaelmina_lab) August 11, 2020
SD Biosensor, Rapigen have tests - but CE marker abroad. 3M, e25Bio, Sherlock (and possibly the big diagnostic companies like Abbott and BD?) too!
C’mon feds! Let’s see the urgency! https://t.co/mRtnCLPkQq
Why this matters
Better testing strategies can save lives; it can help us return to activities that have been shut down or moved online since March. Rapid tests could give us important information at a frequency that is useful and actionable.
But that does not mean we can shed other public health measures.
Yes- PPE, rapid tests, ⬆️ funding are sorely needed, but physical distancing, cloth masks, quarantines, etc. are MINIMUM #COVID19 protocals that @PAHealthDept must enforce in #SUD tx programs (+ courts, jails, prisons) where people have no voice/choice. https://t.co/45GNNMINe4?— Gail Groves Scott (@Gail_G_Scott) August 13, 2020
Cases are rising in the U.S. and schools are preparing to welcome back students this fall. While rapid tests are not going to make COVID-19 go away, it could be a vital part of a reopening strategy. And as anyone who has waited a week, two weeks or longer for a result to come back might say, getting results back quickly can be a game changer.
For up-to-date information about COVID-19, check the websites of the Centers for Disease Control and Prevention and the World Health Organization. For updated global case counts, check this page maintained by Johns Hopkins University.
You can follow Chia-Yi Hou on Twitter.
Note: The number of ID NOW tests shipped each week has been added.