Who should get a COVID-19 antibody test, and when
TAMPA, Fla. - It was a way for people to get tested for COVID-19 exposure earlier in the pandemic, and now doctors are putting antibody testing into context for anyone wondering about their current level of protection as federal officials weigh booster shots.
COVID-19 antibody testing can help doctors treat patients in the hospitals, see how high levels are in vaccinated vulnerable people, or show your exposure to the virus.
"One scenario we utilize antibody testing is when somebody comes into the hospital and they're sick with COVID right now, there are some medications that we may want to give somebody while they're hospitalized where they can't already have high levels of antibody in their blood. And so for that reason, we would do antibody testing for different evaluations, for different medications," said Dr. Jason Wilson, Tampa General Hospital’s associate medical director of the adult and USF Health associate professor.
Dr. Wilson said it’s an evolving science that has different types of tests that show results that don’t all mean the same thing.
"If you just go out and get an antibody test and I give you a number back, I don't think that number means much," said Wilson. "The question just becomes, what do you do with that information? So if you're trying to make workplace decisions and you've got a person who has a high antibody number, what does that number mean in terms of decision you're trying to make?"
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Scientists said the problem is antibody testing is not standardized. The numbers can all mean different things depending on where you got the test, so antibody testing is not widely recommended for the general public.
"So I know that it's we will all want to make things as simple as possible to say I have antibodies or I don't. I need a vaccine or I don't. But in this case, it's more nuanced. That's why experts and physicians have to interpret the data and give people the recommendations about what to do," said Dr. Michael Lauzardo, a physician and deputy director of the Emerging Pathogens Institute at the University of Florida.
The recommendation is getting vaccinated against the virus. Studies show the antibody levels from the vaccines remain strong, but scientists said they do start to drop a little over time. So that’s where booster shots come in to help maintain the highest level of protection. Wednesday, Johnson and Johnson and Pfizer announced its doses help.
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"We know that when you give that a third dose, that there's going to be a significant immune response. It's kind of expected but nice to see the science," said Lauzardo.
Dr. Lauzardo said vaccinated people should not worry about their antibody levels while they wait for potential boosters. And for unvaccinated people, public health experts said relying on antibodies from the virus won’t have as much protection as a vaccine.
"So if you got infected early in the pandemic, your antibody response probably is not as broad and it may have holes in it from to the variants that we get. The vaccines that we have in the United States seem to induce a really broad set of antibodies that recognize so they're less susceptible to the variants that are out there," said Dr. Michael Teng, a virologist with USF Health. "There's a difference in magnitude. So you get a lot more antibody from the vaccinations, particularly the MRNA vaccinations. But we don't know if the duration is the same for the MRNA vaccines versus the natural infection."
Doctors and scientists said people should get the shot if they haven’t yet because the vaccines are the best protection.
"It works, but just people need to remember that their current series works and they need to get vaccinated if they're unvaccinated," said Lauzardo.