An expert’s opinion on the use of rapid antigen tests to tackle COVID

As winter approaches and the holidays approach, the COVID-19 epidemic has reached a new concerning phase. The emergence of the omicron strain, along with rising infection rates, has left many individuals uncertain about their vacation plans.

On Dec. 2, President Joe Biden detailed a number of initiatives to address the COVID-19 epidemic, including allowing private insurance to compensate for at-home COVID-19 rapid antigen tests. Along with immunization, rapid antigen tests remain one of the most efficient methods of tracking and reducing SARS-CoV-2 transmission, the virus that causes COVID-19.

Even though COVID-19 rapid antigen tests have become ingrained in the majority of people’s daily lives, many individuals continue to have doubts regarding the distinction between antigen and PCR tests, as well as when and how to utilize them. learn more about different types of rapid antigen tests and how to use them at

I am a molecular scientist at the University of Massachusetts Chan Medical School. Since April 2020, I’ve been a member of a team working on a National Institutes of Health-funded effort called RADx Tech, which aims to assist firms in developing quick tests to diagnose COVID-19 infection.

How are fast antigen assays performed?

Rapid antigen tests are used to identify a component of SARS-CoV-2 protein known as an antigen. To begin, use a swab to collect a sample from your nose or mouth, as indicated. You combine the sample with a liquid that liquefies the virus. The liquid is then applied to a test strip that contains a narrow line of antibodies specific for SARS-CoV-2 painted on it. Antibodies are Y-shaped proteins that identify and bind to antigens. If the antibodies recognize the viral proteins or antigens, a colorful line indicates the presence of SARS-CoV-2 on the test strip.

These tests are useful since they are straightforward to administer and provide findings rapidly, generally within 15 minutes. Additionally, rapid antigen tests are quite affordable, costing between $10 and $15 for each test (though they are much cheaper in other countries). In comparison, PCR rapid antigen tests often need laboratory equipment and specialists, take 12 hours to several days to complete and cost $100 or more, but there are several free options.

Biden also mentioned plans to give 50 million free rapid antigen tests to community health care practitioners for those without insurance during his remarks. Be ready to respond swiftly: In late November, 100,000 individuals signed up for free antigen COVID rapid antigen tests in less than 24 hours in New Hampshire.

The Food and Drug Administration approved around a dozen rapid antigen tests for SARS-CoV-2 in early December 2021, indicating that these tests fulfill specific performance and accuracy requirements.

When should quick testing be used?

If you exhibit any of the symptoms of COVID-19, regardless of vaccination status, you should seek immediate rapid antigen tests using PCR or antigen.

SARS-CoV-2 is very contagious, even if you do not exhibit symptoms. The sooner you discover whether you have COVID-19, the sooner you may isolate yourself, preventing transmission to others. Early rapid antigen tests are particularly crucial since new medications, such as those developed by Merck and Pfizer, are most effective when given early in the course of an infection, just after symptoms manifest.

If you obtain a negative antigen test but continue to feel poorly, you may have gotten a false negative result. Isolate yourself from people and make an appointment with your physician to discuss your symptoms. If you get a positive test, you should remain at home and notify your health care physician immediately.

If you do not have symptoms but have been in close contact with someone who has COVID-19, the appropriate course of action is determined on your vaccination status. If you are completely vaccinated, the CDC advises waiting five to seven days following exposure to get a PCR or rapid antigen test. If you are not completely vaccinated, seek immediate medical attention. If you do not develop symptoms after exposure, you should be retested five to seven days later.

SARS-CoV-2, like many other respiratory viruses, takes many days to develop up in your body after exposure. Because the quantity of viral protein is very low at this early stage of infection, a fast test may miss your illness. This is why, for many antigen tests, serial rapid antigen tests over many days with at least 24 hours between tests are suggested. Rapid antigen tests are most accurate when an individual is infected since this is when the virus is most concentrated in the respiratory tract.

Serial antigen testing – often two to three tests per week – has been proven to be comparable to a single PCR test. Bear in mind that a test provides an estimate of your SARS-CoV-2 status at the time of the test. It is possible to test negative during the early stages of infection, particularly with antigen testing.

What is the future of COVID-19 at-home rapid antigen tests?

Despite everything we have learned, there is still much more to learn about the most effective approach to perform fast testing. Our research team is now performing many studies to bridge these gaps.

One of the questions we’re investigating via a program called STOP COVID-19 is how individuals utilize home rapid antigen tests when their infection risk is low vs high. For example, someone who wears a mask inside and avoids eating out is considered low risk, but someone who is not vaccinated and congregates with a large number of individuals without masks is considered high risk. 

Additionally, we want to know if individuals will comply with a rapid antigen tests routine after exposure and whether they will report their home test findings to their local department of public health.

Another significant subject our team is investigating is how antigen testing compares to polymerase chain reaction (PCR) tests for diagnosing COVID-19 in patients who are positive but do not exhibit symptoms. Separately, national research called Test Us at Home is gathering critical data that will assist us in answering this issue in the coming months.

Rapid antigen tests are a very beneficial tool in the battle against the COVID-19 pandemic. When utilized appropriately and in conjunction with other techniques like vaccination, mask usage, and basic cleanliness, these steps may assist in limiting the spread of SARS-CoV-2 this holiday season.

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