As U.S. states begin lifting stay-at-home orders, one idea that has been floated to speed up the return to normal life is to issue “immunity passports” to people who test positive for antibodies to the coronavirus, which causes COVID-19.
“Some people have suggested issuing immunity passports and I don’t think that any of these tests can be used to interpret that,” Patrick Hsu, a UC Berkeley microbiologist and one of the lead authors of the study, told Yahoo News. “There’s a lot of basic research that’s being done all over the world to try to understand how the presence and the levels of these antibodies correlate to a protective immune response.
In response to a viral infection, the immune system produces cells to attack the virus and antibodies that bind to it and prevent it from replicating. This process, depending on multiple factors, can result in cellular immunity and can help people ward off the worst symptoms of a disease like COVID-19. While antibodies to other pathogens can prevent reinfection, there is no evidence yet that those to the coronavirus are protective in that way.
“Most of these studies show that people who have recovered from infection have antibodies to the virus. However, some of these people have very low levels of neutralizing antibodies in their blood, suggesting that cellular immunity may also be critical for recovery,” the WHO wrote in the summary. “As of 24 April 2020, no study has evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans.