ATLANTA — Covid-19 vaccine booster shots are going into arms across the nation, and some people are turning to the Verify team asking whether they can check their immunity before getting another dose.
QUESTION
Can a Covid-19 antibody test check immunity after getting the vaccine, informing whether someone should get a booster shot?
THE SOURCES
- The CDC
- The FDA
- Dr. Jayne Morgan, Executive Director of the Covid Task Force at Piedmont Healthcare
ANSWER
No, public health experts say Covid-19 antibody tests are not currently recommended to check immunity following vaccination.
WHAT WE FOUND
Antibody tests were popular at the start of the pandemic, and they're popping up again as discussion over booster shots continue.
As a reminder, Covid-19 antibody tests look for antibodies in your blood that fight the Covid-19 virus, and both the CDC and the FDA state you should not use these tests to check immunity after getting the vaccine.
According to the CDC, there are several reasons interpreting antibody tests could be difficult. According to the agency, antibody tests have varying levels of sensitivity, while some antibody testing only detects antibodies from natural infection with SARS-CoV-2. Those tests wouldn't detect antibodies generated from the Covid-19 vaccine.
The FDA lays out further caution and limitations of antibody testing on its website: "Test results from currently authorized SARS-CoV-2 antibody tests should not be used to evaluate a person’s level of immunity or protection from COVID-19. If the results of the antibody test are interpreted as an indication of a specific level of immunity or protection from SARS-CoV-2 infection, there is a potential risk that people may take fewer precautions against SARS-CoV-2 exposure. Taking fewer precautions against SARS-CoV-2 exposure can increase their risk of infection and may result in increased spread of SARS-CoV-2."
Bottom line, even if your antibody test comes back positive showing some defense against the virus, scientists are still figuring out what that means for protection. Right now, there's no magic number, or threshold, correlating protection.
"What we don't know and what we don't have any published studies to show is, what is the level of antibodies needed that actually confers immunity," Dr. Jayne Morgan, executive director of the Covid-19 taskforce at Piedmont Healthcare, explained.
According to Dr. Morgan, the immune response is also more complex than just antibodies as experts have found cellular immune response also plays a role, which antibody tests cannot detect.
"We have to also remember that these vaccines work not only by antibodies but by cell-mediated immunity so these B cells and T cells," Dr. Morgan explained. "That's also incredibly important in our protection against this virus. So it's multilayered...and so because of that, we are asking and advising that we not use these tests as guides, nor as indicators of what your immunity status could be."
As a result, experts recommend following public health guidance when deciding whether you need a Covid-19 booster shot.