What You Need to Know About Antibody Tests for COVID-19

From The Daily Signal.com (April 19):

Returning to a semblance of normalcy in this country will require the ability to gauge a person’s immunity status to the COVID-19 virus using serology tests—that is, blood tests that detect antibody levels.

People who were infected by the virus and recovered generated a durable immune response by developing antibodies to antigens specific to the virus.

That is to say, the body’s immune system creates molecules called antibodies that are designed to target and attack certain unique features of the virus called antigens.

People who have developed the antibodies to the virus are able to fight it off if the virus enters their bodies again, so those with the antibody are unlikely to be reinfected with the virus and unlikely to be able to transmit the virus to anyone else.

In this way, knowing the immune status of the population will be important to assessing the risk of the community returning to work.

Furthermore, being able to detect an individual’s immune status will also help public health researchers and officials determine the virus’ penetrance, the extent to which it has infected the population.

This is possible because certain antibodies persist in the blood long after the infection, even if an individual never showed any symptoms from the virus.

The ability to detect previous asymptomatic infections will be important because recent evidence suggests that a potentially large proportion of infected people never show symptoms.

Universal COVID-19 screening on hospital labor and delivery wards in New York City found that, of the women who tested positive for the virus, 29 out of 33 were asymptomatic at diagnosis. Of those 29 women, 26 of them remained asymptomatic, while only three developed fevers.  [read more]