The US Food and Drug Administration authorized a coronavirus antibody test from Abbott Laboratories on Sunday, bringing the total number of FDA-authorized antibody tests to eight.
The Abbott test looks for a class of antibodies – called IgG antibodies – that are produced in the later stages of infection. Other tests can detect antibodies produced earlier.
“A negative result may occur if you are tested early in your illness and your body hasn’t had time to produce antibodies to infection,” the FDA wrote in a fact sheet accompanying the Abbott test
Still, the new test could be useful in identifying who has been previously infected with coronavirus, even if they showed little or no symptoms at the time.
The importance of antibodies: Most experts believe that people who have recovered from the virus will have some sort of protection against re-infection, but it’s unclear how strong immunity might be or how long it might last.
“We expect that most people who are infected with #COVID19 will develop an antibody response that will provide some level of protection,” the World Health Organization wrote in a series of tweets Saturday.
“What we don't yet know is the level of protection or how long it will last," another tweet said.
Read the WHO's tweets: