As we appear to be reaching the peak of the coronavirus outbreak in some parts of the U.S., public health officials have started thinking about what happens next. Having widespread, accurate testing for COVID-19 is necessary in order to make it possible for essential workers to return to their jobs, and eventually, reopen society. But how will we keep track of who has developed antibodies after surviving a case of COVID-19 and should be permitted to go out in public? One option — which has already been implemented by researchers in Germany, and is being considered by the United Kingdom and Italy — is to have some form of documentation verifying a person’s immunity to the virus. 

Last week, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNN that the federal government is considering issuing some type of immunity certification to those who have recovered from COVID-19. “I mean, it’s one of those things that we talk about when we want to make sure that we know who the vulnerable people are and not,” he told CNN. “This is something that’s being discussed. I think it might actually have some merit, under certain circumstances.”

But before we get to the point of having immunity cards, there is a lot that has to happen first. Here’s what we know so far about the science behind our current testing capabilities, the feasibility of rolling out a program, and the legal and ethical implications of this type of policy.

Prior to implementing any type of program using immunity cards, Dr. Victor Herrera, an infectious disease specialist and associate CMO for AdventHealth Orlando, says that there are three boxes we must check: first, having a reliable test with high levels of sensitivity and specificity; second, understanding what it means to have COVID-19 antibodies and whether they will protect a person against the virus; and third, knowing how long the antibodies last. “I think everybody agrees that antibody testing is a very important tool until we have a vaccine,” he tells Rolling Stone. As medical professionals look ahead, antibody testing in particular might be key. 

Given how thirsty we are for any type of research on SARS-CoV-2, two small studies out of China and South Korea — which both appear to indicate that people who have had COVID-19 could become reinfected — have been in the news a lot. But Dr. Jessica Justman, associate professor of medicine in epidemiology and the senior technical director of the International Center for AIDS Care at Columbia University Mailman School of Public Health, says to take these studies with a grain of salt. 

First of all, both of the studies involve tests for the RNA of the virus — not the antibody tests that would be required for issuing immunity cards. The method used to conduct these tests involved sticking a long cotton swab to the very back of the nose. “If you don’t get your specimen properly, it might appear negative when in fact, virus is there,” Justman explains. Then, a week later, if a person has another test that was conducted properly, they may test positive, making it look like they were reinfected, though they may have been infected the whole time. “You have to view these kinds of initial studies with small numbers of patients with some skepticism,” she tells Rolling Stone. “If we start to see similar patterns emerging from larger studies — and especially several different studies from different research teams — then we might have something to talk about.”

The antibody tests currently being used have been made available through the Food and Drug Administration’s Emergency Use Authorization — a policy used during public health emergencies. “An Emergency Use Authorization is not a full authorization by the FDA,” Justman explains. “So you can’t say that these are tests that are approved. But given the emergency, FDA has decided to open things up and let various groups — particularly commercial companies — start rolling out tests.” Then, at some point down the line, these companies will have to submit data in order to get actual approval from the FDA. “I think that many people are working very hard on this and it’s going to improve,” he says. “Once the dust settles, the better tests will emerge.”

As Herrera explained, the new antibody tests will need to have high levels of sensitivity and specificity. “In this case, sensitivity tells us how well a test does at correctly detecting antibodies that are in a sample,” Justman explains. “And specificity tells us how well a test does at correctly identifying samples that do not have SARS-CoV-2 antibodies.” At this point, she says that we really need a “gold standard test” where newer tests could be compared to the results of a test that we know works — something we don’t have at the moment. Finally, the tests we have now don’t let us know whether the antibodies someone has developed to SARS-CoV-2 are actually effective in neutralizing the virus — a piece of information that is crucial in the testing process. “Or are they just there, but not doing anything useful?” Justman says.

There are also questions about immunity to this novel coronavirus, including whether the immunity would be full or partial — similar to the type of immunity we get with a typical flu shot, where it protects against one strain of influenza while still leaving us somewhat vulnerable to becoming infected by other strains, Justman explains. And at this point, it’s still unclear how long any type of immunity would last, whether it’s a lifetime, a year, or a few months. For example, Fauci has predicted “a few years” of durable immunity. Others, like Dr. Peter Openshaw, professor of experimental medicine at Imperial College London, aren’t as optimistic. “My guess is that the protective immunity will last at least three months — that’s the worst-case scenario,” he told Bloomberg Businessweek 

And yet, even if immunity cards do emerge as the best way forward, there’s a lot to consider. Justman points to the yellow fever immunization cards given to people in Africa who have been vaccinated against the disease as a potential model for immunity cards in the U.S. “For crossing borders, I could imagine some kind of immunity card,” she says. But Justman stresses that it’s important that we look at the other end of the spectrum too — like whether immunity cards would be required in order to go into a grocery store. “That would be too much,” she says, noting that she’s unsure how U.S. citizens would react to having to show a document to be allowed into a supermarket. “But I think people could go along with it to cross an international border,” she adds. 

There are also logistical considerations. For example, if immunity only lasts a year, would we need to get new cards annually? “And if we’re talking about an app on your phone, would it go away?” Justman says. “We still have a lot of details to work out. The problems would not be insurmountable but the details will be complex.” As Henry T. Greely, a Stanford law professor who specializes in ethics wrote in a recent article for STAT News, an immunity card system could mean problems with verifying applicants’ claims and identities, which could result in a black market in forged immunity cards.

There would also be questions about who has access to the antibody testing necessary to get an immunity card. We’ve already seen how being famous and/or being wealthy can open doors when it comes to getting the basic coronavirus test, and similar disparities are likely to emerge once antibody testing and any form of an immunity card become available. 

But beyond the logistics, immunity cards themselves also raise some serious ethical and legal questions, given that they are based on the concept of dividing society into two classes of people: those who have COVID-19 immunity, and those who don’t. “My instinct is that this doesn’t seem like a very good idea for a variety of different reasons,” Dr. Daniel Goldberg, an attorney and associate professor at the Center for Bioethics and Humanities at the University of Colorado Anschutz Medical Campus tells Rolling Stone

As an expert in stigma, Goldberg explains that anytime people’s social status is altered on the basis of having a disease or exposure to that disease, there is cause for concern. Typically we see situations where having a communicable disease damages a person’s status, resulting in adverse social consequences because of the stigma. (See: Mary Mallon, aka Typhoid Mary.) But an immunity card system would be the inverse, indicating when a person who is thought to be immune to the virus achieves a positive social status, along with the resulting benefits — like being able to visit friends or go to restaurants. And it’s not only social benefits that would come with an immunity card: according to Goldberg, there would be “real, stark legal benefits” as well. “You’d get to go to work. You’d get to go to the gym. You get to be outside,” he says. “It’s problematic from an ethical standpoint to do that on the basis of disease status.” 

There would also be major implications when it comes to disability law — namely, that having a normal immune system without evidence of a prior infection could potentially count as a disability. “It’s weird to think about how someone not having a disease could disable them,” Goldberg explains. “But it’s actually possible under the ‘regarded as’ prong of the Americans with Disabilities Act, which basically says that even if you don’t actually have a disability, if you’re regarded by others as having a disability that substantially limits major life activity, then you get the protections of the ADA.” With regards to immunity cards, Goldberg says “it’s possible that this violates some legal provisions with regard to how people have to be treated in case of disease status,” he says.  

Overall, Goldberg says that the benefits of immunity cards are vastly outweighed by the harms, but thinks there is a better way to reopen society — one that doesn’t create two classes of people based on disease status. Instead, what Goldberg and some other public health experts have proposed is a system of case-based mitigation, which would involve identifying and monitoring emerging hotspots before there is community-wide spread, and placing restrictions on specific neighborhoods, where aggressive public health interventions would take place. Meanwhile, everyone else could continue to go to work and live their lives (within reason). Goldberg says that in theory, the ideas behind case-based mitigation and immunity cards are very similar, both involving identifying people for whom it is safe to move around. The difference is that immunity cards would accomplish this in a way that would change people’s social status based on whether or not they have immunity to a disease.