If I have antibodies to the COVID-19 virus, or if I recovered from the disease, am I protected? These are the two burning questions workers and employers are asking today. The answer, at least from what we know today is bound to be unsatisfying—we don’t know.
Mounting evidence from Italy and elsewhere raises serious unknowns about positive antibody tests for SARS-CoV-2. Not all people who recover from the virus make high levels of antibodies and in some cases, people make no antibodies at all. Even those who do make the antibodies may not make the right ones, the so-called neutralizing antibodies that inactivate the virus in the test tube. In some studies, only 15% of those who tested positive for SARS-CoV-2 antibodies made these neutralizing antibodies. And even among those with the “right” type of antibody, there is a question over how long protection against a new infection might last, or if there is any real protection at all.
All these questions make it difficult for employers to rely on an antibody test, or even successful convalescence, to determine the risk for infection in the workplace. To be sure, anyone who tests positive for an active infection—whether they are symptomatic or not—should be excluded from the workplace. That much is clear. But even someone who tests negative is not necessarily good to return to work, given how many tests fail to detect people who are actually infected and infectious.
Originally published on Forbes (May 4, 2020)