Text size

The Biden administration is spending $ 1 billion on rapid home antigen testing for Covid-19.

Spencer Platt / Getty Images

About the Author: Gigi gronvall, immunologist, is Principal Investigator at the Johns Hopkins Center for Health Security and Associate Professor in the Department of Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health.

After a few weeks in early fall, when rapid Covid-19 antigen home testing was in high demand but scarce, it is now starting to become more available thanks to substantial government investments. This is good news because these tests are an important tool in reducing cases. They can be used to diagnose Covid-19 in less than 30 minutes.

The Biden administration recently announced it would buy $ 1 billion worth of tests. The Food and Drug Administration has cleared manufacturers of additional tests to market the tests in the United States, bringing the total number available in retail stores and drugstores to 10. The National Institutes of Health is investing $ 70 million in US bailout funds to validate the test. data required for FDA clearance. Retailers also agreed to sell the tests at cost, which lowered prices by around 30%. With more tests in the market and with government funding, the costs per test are expected to drop further. These are all great developments that should make rapid antigen testing much more available, affordable, and will increase its use.

Rapid antigenic tests are a great tool to help stop the spread of Covid-19 because they are good indicators of whether a person is contagious at the time of the test. Their ability to give near immediate and actionable results is superior to other tests including PCR, the Covid-19 diagnostic which has so far been considered the gold standard. When a person has Covid-19 and breathes a lot of viruses in the air that can be inhaled by others, rapid PCR and antigen tests are very comparable in their sensitivity. It is at this point that people should know that they are a potential danger to others and should self-isolate to prevent the spread of the virus.

Covid-19 diagnostics that use PCR are sensitive because unlike rapid antigen tests, there is an amplification step, so very weak signals can be amplified and detectable. Theoretically, using PCR, a person can be diagnosed with Covid before they become actively infectious. Unfortunately, PCR tests have to be processed by a lab, which adds time to the results. These often take 24, 48, 72 hours, sometimes longer, to receive. This delay can eliminate the benefit of early warning. In addition, PCR tests can also occasionally be too much sensitive for convenient use. PCR can also detect weak signals after a person has recovered from Covid-19, sometimes for weeks after they were at risk of infection to others.

Rapid tests are easy to administer on their own, or for a child 2 years of age or older, at home. If the instructions seem confusing, the test makers have videos on their websites that walk people through the process. Guidance is also available on the sites of the test manufacturers if people are having difficulty interpreting the tests.

Rapid antigen tests are extremely useful in diagnosing active Covid-19 infections, but they present challenges. Perhaps most importantly, a home test does not usually produce a “verified” result. If an airline demands a negative test, they will not speak to someone who has performed a rapid home antigen test. There are services that will do the testing at airports, for example, which can be expensive. There are also services that allow a medical technician to directly observe a person being tested.

Another potential problem is that it can be difficult to run multiple tests at a time to track the results and when the tests have started. According to the instructions that were part of the FDA test authorization, the results should be “read” within a short period of time (usually half an hour). This delay makes batch processing a difficult undertaking for a school nurse, for example, who may want to process multiple tests at once while dealing with other competing priorities. This has been a serious limitation of certain ‘test-to-stay’ protocols, in which students who may have been considered close contact of a confirmed Covid-19 case are allowed to stay in school as long as they are continue to test negative every day. . If test manufacturers validated tests to make them longer read, it would make them easier to use in schools.

Now that there is potential therapy for Covid-19, rapid antigenic testing can serve another important function: testing to treat. Merck’s molnupiravir is an investigational drug that has been shown to be effective in reducing hospitalizations due to Covid-19. Its effectiveness, however, is most evident when given in the early stages of the disease. A home test giving a quick result could lead to a prescription of the drug much faster, when it could be the most beneficial.

The high demand for rapid Covid-19 antigen tests should be a signal to test makers that people want immediate access to reliable health information for themselves and their children. For example, there is no reason why home flu tests should not be available, or tests for other common childhood illnesses. It would be useful for caregivers to know if an illness requires a child to be seen immediately or if an illness is likely to pass within a day or two without taking a sick and tired child to a doctor, thereby risking further exposure. to other diseases. A thriving home testing market could also be helpful for emerging diseases: Covid-19 will not be the last pandemic we face. Making rapid home tests widely available could help limit the spread and lessen the impact of infectious diseases, when and where they occur.

Guest comments like this are written by authors outside of the Barron’s and MarketWatch newsroom. They reflect the views and opinions of the authors. Submit your comments and other comments to [email protected]

Leave a Reply

Your email address will not be published.