Can COVID-19 Tests Detect BA.2 Variant?

2022-04-24 02:49:41 By : Ms. Joy Zhao

Alyssa Hui is a St. Louis-based health and science news writer. She was the 2020 recipient of the Midwest Broadcast Journalists Association Jack Shelley Award.

Nick Blackmer is a librarian, fact-checker, and researcher with more than 20 years’ experience in consumer-oriented health and wellness content.

As the Omicron surge eases and COVID-19 cases trend downwards in the U.S., many people are returning to their pre-pandemic routines.

However, researchers are still on high alert as the highly transmissible Omicron subvariant known as BA.2 continues to spread. According to the World Health Organization (WHO), reported sequences of BA.2 have been increasing in recent weeks on a global level. The subvariant is now the dominant strain in the U.S. according to Centers for Disease Control and Prevention (CDC) data.

But because BA.2 is considered to be relatively new, can the subvariant evade COVID-19 tests and give people inaccurate results?

Health experts say it's not likely.

Despite BA.2 being a new variant, there is no proof or confirmation that shows BA.2 evades COVID-19 tests or affects the test from giving a user an accurate diagnosis, Amesh Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health, told Verywell. 

“There’s no evidence that Omicron evaded tests and there was no faulty testing with Omicron BA.1 or BA.2,” Adalja said.

While variants including BA.2 do not impact the accuracy of rapid antigen COVID-19 tests, according to Adalja there are other factors that do. These can include the swab not being collected from the nose or throat properly, the swab or mucous sample being accidentally contaminated during collection, the nasal swab or throat swab may not have been kept at the correct temperature. Other factors like the timing of when you take the test are important, too.

Scientists are still learning about the BA.2 variant and its potential effects on testing, but the CDC’s director Rochelle Walensky, MD, MPH, said BA.2 does not appear to evade vaccines or immunity any more than the previous strain of Omicron.

There are different types of COVID-19 tests: polymerase chain reaction (PCR) or rapid at-home antigen tests.

When people generally get tested for COVID-19, rapid antigen tests don’t identify which variant you may be infected with, it just gives you a positive or negative result, Adalja said.

“The test results you get from BA.2 infection are the same as you would have gotten with Alpha, Delta, or Beta. Those tests just tell you that you’re infected with [COVID-19],” Adalja said. “It doesn’t necessarily matter which variant you may have and there’s no way for a person to know which variant they’ve been infected with, there’s no easy way to do that.”

While normal tests can’t detect variants, scientists can run a process called genomic sequencing to determine which variant is at work.

But whether you know which variant you have or not after getting tested for COVID-19, Adalja said it should not make much of a difference. If you test positive you should continue to follow health protocols like isolating and contact tracing.

Knowing which variant caused the infection is mostly beneficial for researchers, local health departments, and health care professionals, especially when it comes to recommending certain monoclonal antibodies—which are antibodies made in a laboratory designed to fight off a particular infection and is typically given as an infusion—to patients with COVID-19.  

“For people who are going to be getting monoclonal antibodies as treatments, there are certain monoclonal antibodies that didn’t work against BA.1 and there are certain monoclonal antibodies that don’t work against BA.2,” Adalja said. “So from a clinician standpoint, it’s important to have an understanding of what the prevalence of the various variants is in your area.”

If people are getting infected with COVID-19 right now, Adalja said it’s most likely one of the variants of Omicron.

Bernadette Boden-Albala, DrPH, MPH, director and founding dean at the University of California, Irvine Program in Public Health, told Verywell that people should test a few times to make sure results whether positive or negative are truly accurate.

Certain treatments like monoclonal antibody therapy or Pfizer’s COVID-19 pill need to be given as soon as possible after symptoms occur to help people with chronic medical conditions feel better faster, shorten the duration of any symptoms, and reduce the need for hospitalization. Making sure you get accurate test results can be crucial when trying to access some of these treatments.

If you’re feeling sick or have been in close contact with someone who had COVID-19, it’s crucial to get tested. There are no reports suggesting that BA.2 manages to evade testing and provide inaccurate results. But you should test a few times to make sure a negative result is accurate. You can also try out the CDC’s tool for understanding what type of test you should take and when.

According to Boden-Albala, testing guidelines and recommendations have not changed. People should continue to follow guidance from the CDC despite existing and potential new variants. This means getting tested when you have COVID-19 symptoms; waiting at least five days to get tested after a known suspected close contact with someone with COVID; and testing before and after travel, when asked by your doctor, or for routine school/workplace screenings.

The CDC states that several negative test results increase the confidence that you are not infected with the virus that causes COVID-19.

And if you’d already been infected with Omicron, you may have some additional protection against BA.2.

“Early studies show that if you’ve previously had Omicron, you likely have good protection against BA.2, at least for now,” Boden-Albala said. “We’re still learning more about how long that immunity lasts.”

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 our coronavirus news page.

Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.

Thank you, {{}}, for signing up.

There was an error. Please try again.

World Health Organization. Statement on Omicron sublineage BA.2.

Food and Drug Administration. Coronavirus testing basics.

Centers for Disease Control and Prevention. What is genomic surveillance?

Department of Health and Human Services. What are monoclonal antibodies?

Duke University Health System. Monoclonal antibody treatment available for eligible people with COVID-19.

Thank you, {{}}, for signing up.

There was an error. Please try again.