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Video: Understanding COVID-19 Antibody Tests

In this video, we take a look at COVID-19 antibody tests, which can reveal whether someone was previously infected with the novel coronavirus — and explain why a positive or negative result may not always be so easy to interpret.

Antibodies are Y-shaped proteins the body generates as part of an immune response to a specific pathogen. Because the proteins are highly specific, tests that can check for the presence of antibodies in a person’s blood have the potential to identify people who have already encountered the virus.

Such information is critical to figuring out how widely the novel coronavirus, or SARS-CoV-2, has spread, and could also be used to identify people who are immune.

But the tests are only beginning to be rolled out, and many are not accurate enough to use.

Further complicating any use of the tests in the clinic is that scientists don’t know whether antibodies can protect someone from becoming infected again with COVID-19. While experts strongly suspect that will be the case, it’s not known for certain yet, nor it is clear how long any potential immunity would last.

For more on antibody tests, including the basics of how the tests work, see our story, “Q&A on COVID-19 Antibody Tests.”

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