Key Takeaways
- At-home rapid antigen testscan be used to detect the BA.5 variant of COVID-19, according to experts.
- To get the most accurate COVID test results, you need to follow the instructions exactly and test multiple times over a few days.
- The BA.5 variant spreads easily. If you are infected, you might be able to spread it to other people before you have a positive COVID test—even if you don’t feel sick.
The Omicron BA.5 variant—the strain of COVID-19 that’s currently dominating in the United States—is good at evading immunity from both vaccines and previous COVID infection. There’s also concern that rapid at-home antigen tests are less effective at detecting the variant, too.
When Omicron first hit in late 2021, the FDA said that antigen tests do detect the variant but that the tests may have reduced sensitivity.
COVID Test Sensitivty
A diagnostic test’s sensitivity is a measure of how often it shows a positive result when a person really is sick.
If a COVID test has low sensitivity, it means there’s a higher chance it will give a negative result to people who are sick (false negative).
Researchers have been trying to figure out how well rapid tests spot an Omicron infection. They’ve concluded that while at-home COVID tests can pick up Omicron variants—including BA.5—there are some key steps that people need to take to get an accurate result.
What We Know About Omicron BA.4 and BA.5
Are Rapid Tests Ready for BA.5?
Phyllis Kanki, DVM, DSc, a professor of health sciences at Harvard T.H. Chan School of Public Health, told Verywell that “studies conducted—including our own—showed that rapid antigen tests maintained their ability to effectively detect Omicron.”
Since BA.5 is part of the Omicron family, Kanki said it’s not been anticipated that at-home tests will be less effective.
When Should You Get Tested After a COVID-19 Exposure?
Nathaniel Hafer, PhD, an assistant professor of molecular medicine at the University of Massachusetts Medical School, agreed with Kanki, adding that antigen tests can detect BA.5 because of how they are designed.
Hafer said that the test strip on rapid tests has antibodies on it, which are made in the lab. They’re just like the antibodies we have in our bodies that recognize foreign compounds—otherwise known as antigens.
“Those antibodies are designed to bind to parts of the virus,” said Hafer. “Typically, they are binding to what’s known as the nucleocapsid protein, which is one of the most common proteins that’s in the highest abundance in the virus.”
While the spike protein on the SARS-CoV-2 virus has mutated with Omicron variants, Hafer said that the nucleocapsid tends to mutate at a relatively low rate. In other words, the antigen tests can spot the nucleocapsid found in BA.5.
Can COVID-19 Tests Detect the Omicron BA.2 Variant?
How BA.5 May Affect Rapid Tests
While experts say that at-home COVID rapid tests can detect BA.5, there are some key things to be aware of before you test if you want to ensure you get an accurate result.
For example, with the new variant, some people have reported having COVID symptoms and testing negative with a rapid test for a few days before getting a positive result. Others say that they’ve tested negative for two days in a row, only to become positive on day three.
Hafer said there are a few reasons why this could be happening. First, it can take a few days for the COVID virus to build up in the body.
“There can be a period early in the infection where the virus is present, but it’s not present at high enough levels to be detected on these kinds of tests,”said Hafer, adding that this is particularly true when somebody is first showing symptoms, or when they’ve just been exposed to somebody who is COVID positive.
PCR tests typically show a COVID infection one to two days before a rapid test does because they’re more sensitive.
Since BA.5 is highly transmissible and can jump from person to person before they show symptoms, it could be a few days before someone develops obvious symptoms and tests positive.
Another reason that Hafer cites has to do with where the COVID virus is in the body. The Omicron variants seem to be more in the throat than the nose, which could affect the sampling technique of antigen tests.
Research by the Ontario COVID-19 Science Advisory Table found that rapid antigen tests are less sensitive for the Omicron variant compared to theDelta variantwhen samples are taken from the nose—especially in the first couple of days after infection. Therefore, the researchers concluded that oral-nasal samples may detect Omicron more reliably.
What You Need to Know About the Omicron BA.2.12.1 Subvariant
How to Use Rapid Tests for BA.5
For any strain of COVID, the key to getting a reliable result from a rapid at-home test is taking it the right way. According to Kanki, “the accuracy of the rapid tests requires that the instructions for the rapid tests be followed completely.”
Hafer adds that this means if a test’s package says to use a nasal swab, don’t take it upon yourself to swab in a different way.
Taking more than one rapid test also improves accuracy. Hafer said that many of the tests are designed to be used in sequence—for example, taking two tests 24 to 48 hours apart.
What to Know About Omicron BA.5 Reinfections
Research has shown that serial testing multiple times per week increases the accuracy of rapid tests.Hafer said that this is because “especially early on, there can be that period of virus increasing in the body.”
Once you’ve taken a test and gotten results, Hafer said to “wait another 24 to 48 hours before you do a second test.” According to Hafer, the results of those “two tests together have the combined accuracy, in many cases, of a PCR test.”
Kanki adds that at-home rapid tests are very good at detecting the virus during the highest peak of virus replication (usually when a person shows symptoms).
The bottom line? If you follow instructions and take two or more tests in sequence over the course of a few days, you can probably rely on the information you’re getting.
“The tests still detect Omicron,” said Hafer. “And so people should feel confident that they’re working, and that they can trust the results.”
What This Means For You
At-home antigen tests can detect BA.5. However, to get accurate results, experts advise that you follow the test directions to the letter and take multiple rapid tests a few days apart.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit ourcoronavirus news page.
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Quest Diagnostics. Understanding sensitivity and specificity.
Jüni P, Baert S, Corbeil A, et al. Use of rapid antigen tests during the omicron wave.Sci Briefs Ont COVID-19 Sci Advis Table. 2022;3(56). doi:10.47326/ocsat.2022.03.56.1.0
Smith RL, Gibson LL, Martinez PP, et al. Longitudinal assessment of diagnostic test performance over the course of acute SARS-CoV-2 infection. J Infect Dis. 2021;224(6):976-982. doi:10.1093/infdis/jiab337
:max_bytes(150000):strip_icc()/LauraHensley-f2b33ada37de498ab63980353b85c333.jpg "Do COVID Rapid Tests Work for BA.5? (1)")
By Laura Hensley
Laura Hensley is an award-winning lifestyle journalist who has worked in some of the largest newsrooms in Canada.
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FAQs
Do rapid tests work on ba5? ›
Covid Rapid Tests Still Work for Omicron and BA. 5, But Can Give False Negatives - Bloomberg.
Are rapid tests accurate for Omicron variants? ›Unsupervised SARS-CoV-2 rapid antigen testing with three commercial kits had 70% to 81% sensitivity during the period when Omicron emerged and became predominant in the Netherlands.
Do rapid tests recognize Omicron? ›The answer is yes, although the U.S. Food and Drug Administration recently reported that at-home tests known as rapid antigen tests “may have reduced sensitivity” at detecting the omicron variant, says Mary Hayden, MD, chief of infectious diseases and the James Lowenstine Professor of Internal Medicine at RUSH ...
How accurate are home COVID tests for Omicron? ›When you perform an at-home COVID-19 antigen test, and you get a positive result, the results are usually accurate. However, if you perform an at-home COVID-19 antigen test, you could get a false negative result. This means that the test may not detect the SARS-CoV-2 virus that is in your nasal swab sample.
Are Rapid tests just as good as PCR tests? ›Rapid Antigen Tests
This test involves collecting nose and throat secretions via nasopharyngeal swab and then examining them for protein fragments specific to the COVID-19 virus. While these tests provide quick results—within 15 minutes—they are generally considered to be less accurate than PCR tests.
PCR tests are generally considered more accurate than rapid tests, but rapid tests have benefits that PCR tests do not have—for example, they provide results faster and for a lower cost. The test that is right for you will depend on why you are taking the test and how soon you need to get results.
How reliable are rapid antigen tests? ›For rapid antigen tests, this includes a clinical sensitivity of at least 80% (for specimens collected within 7 days of symptom onset) and a clinical specificity of at least 98%.
Can you test negative for Covid and still have it? ›Sometimes an at-home COVID-19 antigen test can have a false-negative result. A negative at-home test is not a free pass if the person taking the test has symptoms.
How long does it take to test negative after Omicron? ›For most omicron variants in circulation today, this is one to three days, depending on the initial amount of virus you get exposed to.
Does the new strain of Covid show up on rapid test? ›In a study, rapid antigen tests were able to recognize N protein mutations in past and present SARS-CoV-2 variants, as well as more than 99% of potential future variants.
How soon after exposure to Omicron do symptoms appear? ›
When do omicron subvariant symptoms start? The time it takes for an infected person to develop symptoms after an exposure is shorter for the omicron variant than for previous variants — from a full week down to as little as three days or less, according to the Centers for Disease Control and Prevention.
How long does it take for symptoms of Covid-19 to appear after exposure Omicron? ›According to the Centers for Disease Control and Prevention (CDC), COVID has a long incubation period of up to 10 days. On average, the time of exposure to active infection is typically five to six days, however it can be as short as three days with the new virus strain.
Should I trust my rapid or PCR test? ›Another important difference between the two tests is the accuracy rate. Experts say the rapid antigen test is quite likely to be accurate for patients who test positive for COVID-19. However, the rate for false negative results may be as high as 50%.
Why are PCR tests better than rapid antigen? ›PCR tests can detect a much smaller amount of the virus and can therefore determine whether you've contracted the virus much sooner than an antigen test.
How long are you contagious with COVID? ›You are most infectious (or contagious) in the first 5 days after your symptoms start. You can also spread COVID-19 in the 48 hours before your symptoms start. If you never have symptoms, consider yourself most infectious in the 5 days after you test positive.
What is difference between rapid PCR and rapid antigen test? ›How do rapid PCR and rapid antigen tests work? Both standard and rapid PCR tests work by looking for genetic material from the SARS-CoV-2 virus. Antigen tests, on the other hand, look for specific proteins on the surface of the cell. This is what makes PCR tests more accurate than antigen tests.
Is rapid antigen test 100% accurate? ›Rapid antigen tests are most accurate when they are used in people who have signs or symptoms of COVID-19, especially during the first week of illness. People who test negative may still be infected.
Are rapid antigen tests less sensitive? ›Antigen tests for SARS-CoV-2 are generally less sensitive than real-time reverse transcription polymerase chain reaction (RT-PCR) and other nucleic acid amplification tests (NAATs), which detect and amplify the presence of viral nucleic acid.
Which rapid test is most accurate? ›“Studies have shown that nasal tests and saliva tests are more accurate in detecting COVID-19 than throat swabs, and have become the best-practice standard when performing COVID-19 testing,” says Dr. Jain.
Are you still contagious with COVID-19 after 5 days? ›Those with severe COVID-19 may remain infectious beyond 10 days and may need to extend isolation for up to 20 days. People who are moderately or severely immunocompromised should isolate through at least day 20.
How soon after exposure are you contagious? ›
A person with COVID-19 may be contagious 48 hours before starting to experience symptoms. In fact, people without symptoms may be more likely to spread the illness, because they are unlikely to be isolating and may not adopt behaviors designed to prevent spread.
Can you have Covid without a fever? ›Although a fever is a common symptom of this virus, it's still possible to have COVID-19 without a fever, especially within the first few days after being infected. In fact, one study found that just 55.5% of the surveyed COVID-19 patients reported experiencing a fever.
How many days should I isolate after Omicron positive? ›The patient should avoid contact with the family members except for the caretaker. The time for home isolation of omicron infected patients has been decreased to seven days from testing positive if they show no signs of fever for three days in a row, instead of ten days before.
Can you be positive one day and negative the next Covid? ›Unfortunately, yes—it is possible.
What are some of the symptoms of the Omicron sub variant BA 5? ›Like the other Omicron strains that have been dominant in the U.S. since December 2021, experts say BA. 4 and BA. 5 mainly cause cold-like symptoms and respiratory or breathing issues. The CDC reports that people's most common complaints when infected with Omicron include cough, runny nose, congestion, and fatigue.
What medications can I take to relieve the symptoms of COVID-19? ›You can treat symptoms with over-the-counter medicines, such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil), to help you feel better.
How long does COVID sore throat last? ›Most symptoms of COVID-19 last anywhere from several days to 2 weeks. But this can vary from person to person.
When does COVID get worse? ›A person may have mild symptoms for about one week, then worsen rapidly. Let your doctor know if your symptoms quickly worsen over a short period of time.
How sensitive are rapid tests for Covid? ›In people with confirmed COVID-19, antigen tests correctly identified COVID-19 infection in an average of 73% of people with symptoms, compared to 55% of people without symptoms. Tests were most accurate when used in the first week after symptoms began (an average of 82% of confirmed cases had positive antigen tests).
How effective is rapid antigen test? ›Acceptable sensitivity - clinical sensitivity greater than 80% PPA. High sensitivity - clinical sensitivity greater than 90% PPA. Very high sensitivity - clinical sensitivity greater than 95% PPA.
How long do ba5 variant symptoms last? ›
How long do omicron symptoms last? Most people who test positive with any variant of COVID-19 typically experience some symptoms for a couple weeks. People who have long COVID-19 symptoms can experience health problems for four or more weeks after first being infected, according to the CDC.
How long after you test positive for COVID-19 are you contagious? ›Everyone's immune response is different, and we can spread the virus for different amounts of time. Masking on days 6-10 helps reduce the risk that we will get others sick after recovering from COVID-19. Most people are no longer infectious after day 10.
When are you most contagious with Covid? ›People are thought to be most contagious early in the course of their illness. With Omicron, most transmission appears to occur during the one to two days before onset of symptoms, and in the two to three days afterwards. People with no symptoms can also spread the coronavirus to others.
Do people test positive on rapid test? ›If you get a positive rapid antigen test result
If you test positive using a rapid antigen test, it is highly likely you have COVID‑19. You should isolate and follow the appropriate guidelines. You do not need to get a PCR or rapid molecular test to confirm your rapid test result.
PCR Tests are most accurate, if you can get one. If the test results are positive, you are positive, and you should not re-take a PCR test. Your PCR test may be intermittently positive for 90 days following infection and neither a positive or negative follow-up result will change management.
Is rapid antigen test accurate than PCR? ›With more accurate results, PCR tests are the preferred way to go, but antigen tests work for rapid results, as well.
How long after exposure to Omicron do symptoms appear? ›“Most patients are coming in with three or four days of incubation,” Meza said.
How long does it take to test negative for Omicron? ›For most omicron variants in circulation today, this is one to three days, depending on the initial amount of virus you get exposed to.
How long are you contagious with COVID Omicron? ›Those with severe COVID-19 may remain infectious beyond 10 days and may need to extend isolation for up to 20 days. People who are moderately or severely immunocompromised should isolate through at least day 20.