Governments need to be careful about using the presence of antibodies to COVID-19 as a basis for "immunity passport" or "risk-free certificate," to allow a person to travel or go back to work, says the World Health Organization (WHO).
In a scientific brief released last April 24, 2020, WHO stressed, "There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection."
It warns, "People who assume that they are immune to a second infection because they have received a positive test result [for antibodies] may ignore public health advice. The use of such certificates may, therefore, increase the risks of continued transmission."
The "antibody-mediated immunity" was bolstered by studies that show people who have recovered from infection have antibodies to the virus. That reinforced the premise that you can only get COVID-19 once — the antibodies will supposedly protect you from re-infection.
But, as NPR reports, data coming from China and South Korea showed there is "a growing number of its COVID-19 survivors appear to have suffered a relapse of the disease."
In a video report for CNN, Dr. Sanjay Gupta said it is the "IGG" antibody, which appears after the infection is cleared, that might provide immunity, but it is too early to tell how strong and how long the protection it can provide if any.
And, so far, current studies show that high levels of antibody presence do not show increased immunity either. This suggests that researchers have to focus on the antibody's "neutralizing activity."
As Dr. Gupta explains, "It only matters how well [antibodies] work at keeping the virus from entering a human cell. And that can vary from person to person."
Dr. John Roback, the medical director of the blood bank of Emory University Hospital, who helped develop an antibody test in the U.S., told Dr. Gupta, "Not everybody that has high levels of antibodies on the tests we're doing now actually has high neutralizing activity."
At the moment, the antibody test that Emory University Hospital conducts provides "a little peace of mind."
Dr. Roback says, "If you are positive on this test, it indicates you have been exposed and give you a little peace of mind that the cough you had two weeks ago was really COVID-19. It could indicate some of your close contacts should be tested."
For Dr. Gupta, however, the antibody test made him realize, "If you test positive for the antibody, that means you dealt with the infection, and you beat it. Chances are if you are exposed to it again, you could beat it again."
It is important to note here that the donation of blood from COVID-19 survivors is even more crucial to further aid the research of the disease.