As local leaders weigh opening up the economy again, antibody tests for coronavirus are getting a lot of attention. That’s because they can detect whether someone has had the virus in the past, and may be okay to return to work, potentially without being contagious.
But there’s still a lot of scientific research to be done before antibody tests for coronavirus can provide sufficient information for policy makers.
What's an antibody test and how is it different from other coronavirus tests?
The typical diagnostic test for coronavirus is a nasal swab test that looks for the presence of the virus’ genetic material in the body. That’s the test you’d get if you visit a drive-in testing site in Idaho.
Antibody, or serological, tests, on the other hand, look for antibodies in a person’s blood that develop in response to infections like the coronavirus.
“When people make an antibody response to any virus or bacterial infection, they will generate antibodies that have the names IgM and IgG, as well as others,” said Dr. Tom Archie, a family medicine physician in Ketchum.
The test usually involves a finger prick or a blood draw from the arm to test for the IgM and IgG antibodies that develop in response to coronavirus, and some can produce results within 15 minutes.
Why are antibody tests useful?
They can show if someone has already been exposed to the virus and if that person has started to develop immunity.
“What it is potentially helpful for is to get a sense of whether an individual has been exposed to the coronavirus and started to mount an immune response,” Archie said.
With widespread antibody testing across a population, public health officials could better understand how many people have actually been infected by the virus, including those who have been asymptomatic.
What can't antibody tests tell us?
Antibody tests don’t rule out acute infections.
“It doesn’t tell people whether they’re currently infectious or shedding the virus,” Archie said.
And while antibodies typically signal immunity, we don’t know much about what immunity to this particular virus looks like.
“Because this is a new virus, we don't know whether making that antibody response necessarily will bring and produce protective immunity. And we also don't know whether, if that happens, how long it will last,” Archie said.
We also don’t know whether having antibodies means a person can’t infect others, he said.
What to know about antibody tests in Idaho
Last week, Blaine County announced a randomized antibody study. This type of research will help shape a better picture of the extent of the virus’ spread and what immunity might look like.
Antibody tests are available at a few clinics in Idaho. According to the South Central Public Health District, no results from antibody testing sites within that region are being counted toward the state total because the tests being administered there, at the moment, are not authorized by the Food and Drug Administration.
So far, the FDA has authorized one antibody test under an “Emergency Use Authorization.”
Find reporter Rachel Cohen on Twitter @racheld_cohen
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