May 13, 2020 at 4:19 PM EDT – Updated May 13 at 4:19 PM
(CNN) – Antibodies are proteins in the blood that attach themselves to viruses, limiting infection and alerting white blood cells to come in to attack and eliminate the virus.
In many cases, if the body encounters the same virus again, the immune system has leftover antibodies that remember the previous infection.
These cells can either fight off the virus directly or produce even more antibodies to help prevent the infection.
CNN’s Dr. Sanjay Gupta says researchers aren’t entirely sure why this process works so well for some viruses and not others.
“There are some viruses that our immune systems seem to easily forget,” he said.
Immunity may be short lived after encounters with some common seasonal coronaviruses, which can cause the common cold.
That could explain why people can repeatedly get sick with something as simple as a cold, even if they have been exposed to cold viruses before.
People could also be getting exposed to new strains.
And some viruses like the flu mutate frequently, which means old antibodies no longer work against new strains.
“While most experts believe that we’re probably going to have some protection after being infected with the coronavirus, we’re still not sure how long that protection will be or how strong,” Gupta said.
Antibody blood tests check your blood by looking for antibodies. The Centers for Disease Control and Prevention says depending on when someone was infected and the timing of the test, it may not find antibodies in someone with a current COVID-19 infection.
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