As society has begun its push to reopen amid pandemic concerns, interest around the concept of “immunity passports” has been growing in recent weeks.
The idea is based on other viruses in history and facts acquired over the decades surrounding natural immunity. Those who’ve already recovered from COVID-19 have a status of sorts that shows they’ve likely developed immunity to the virus and can move more freely in society, even as others still require social distancing and must keep controlled measures in place.
Is that a practical idea?
Would businesses and public places adapt to the idea of allowing folks with so-called “immunity” to move more freely than others? Would restaurants and gyms open up freely for those with immunity?
What is the science?
Someone who gets infected with COVID-19 will potentially have an immune response, raised antibodies, and other immune cells that can fight COVID-19. They will likely be immune to reinfection, and they also won’t be shedding virus particles themselves that could infect vulnerable or high-risk individuals.
Let’s think about what we know about the recovery from viruses, such as coronaviruses in general, or any infectious disease with very few exceptions. When you have an antibody present, it likely indicates a degree of protection. Think about diseases like measles, chickenpox, or hepatitis b. We can make a reasonable assumption that it would be protective, but natural history and epidemiological studies over a period of months to years will tell us definitely if that is the case.
In the current review of literature and guidance, as it stands today, immunity is likely, but not certain. We as a medical community should move carefully in supporting such immunity concepts as the science is not yet confirmed.
While it is still unknown whether the presence of SARS-CoV-2 antibodies confers immunity, it is important that scientific communities around the world are looking at tests specifically for the broadly neutralizing antibodies that would provide that immunity. This could be a game-changer in the COVID-19 pandemic and effect on society at a global level.
Serologic antibody tests can not only confirm suspected cases after the fact, they can also reveal who was infected and didn’t know it. Up to a quarter of people with a SARS-CoV-2 infection may unknowingly spread the virus because they have minor or no symptoms.
In the treatment of acute COVID-19 infection side, serology tests are being used to screen donor blood for antibodies to SARS-CoV-2. Plasma containing the antibodies from recovered patients is then transfused to very ill patients in an experimental treatment known as a convalescent plasma transfusion. Early results from a small number of Chinese patients, published in JAMA in late March 2020, were promising. The US Food and Drug Administration (FDA) is coordinating a national effort to develop blood-based, antibody-rich COVID-19 therapies. They include convalescent plasma and the hyperimmune globulin derived from it, which ideally will provide passive immunity to people who have been exposed to the virus. This angle of natural infection of COVID-19 favors the hope that natural immunity from COVID-19 is likely.
COVID-19 is a new viral disease and pandemic of epic proportions. We have many unknowns but there is hope. With the global attention that is being paid in terms of suffering and investment of the scientific community including clinical trials for testing, treatment, and future vaccines, I stand optimistic.
