The Problem With Immunity Certificates

(Bloomberg Businessweek) -- During the Great Plague of London in 1665, houses where the infection appeared were painted with a red cross and sealed, condemning the occupants to death. Now the idea of visibly identifying the infected is being turned on its head as governments around the world look at how to reopen economies shattered by the coronavirus crisis.

With hundreds of millions forced to stay home to stop the spread of the virus, politicians and public-health experts are searching for safe mechanisms to allow people to return to work without sparking a second wave of infections. Officials and scientists in Italy, Germany, and other countries are considering giving certificates to people who’ve recovered from Covid-19, the illness caused by the coronavirus. The certificates would allow them to escape restrictions, while the uninfected might have to remain isolated until a vaccine or treatment is found. U.K. Health Secretary Matt Hancock has even floated the idea of an immunity wristband.

“All countries are discussing what the exit strategy could be,” says Hans-Dieter Volk, head of Germany’s Institute of Medical Immunology at the Charité-Universitätsmediz in Berlin. “We cannot continue this way. Everybody knows it.”

Wearing a bracelet or waving a piece of paper to show your immune status might sound like the plot of a dystopian novel, and scientists and public-policy experts are warning the prospect of “immunity passports” could make the current crisis worse.

For one, they worry it could create a two-tiered workforce and perverse incentives for people to try to contract the virus, particularly millennials who might feel their chances of surviving it are high. “Like the ‘chickenpox parties’ of old, some workers will want to get infected,” says I. Glenn Cohen, a bioethics expert at Harvard Law School, referring to when parents deliberately exposed children to others with chickenpox at a young age, when symptoms tend to be milder. “That sounds crazy, but if having the antibodies becomes the cost of entering the job market and thus feeding your family, there may be workers who feel pressured into it.”

Governments, companies, and researchers around the world are trying to roll out blood tests for antibodies against the virus (antibodies are proteins produced by the immune system that help defend against pathogens). The tests could show who’s been infected and holds some immunity—even people who didn’t have symptoms. Testing for immunity raises thorny questions about whether antibody-positive workers might be favored for jobs, especially in consumer-facing industries like restaurants and retail.

For now, giving privileges to people with antibodies may be the price of getting the economy moving again, as long as governments provide enough support for those without a job, says Allison Hoffman, a professor at the University of Pennsylvania who specializes in health-care law. “From a policy perspective, it’s not especially worrisome if the rest of the population has good unemployment coverage,” she says. “It would speed economic rebuilding, which I think everyone would want, whether employed or not.”

The bigger problem: Scientists still don’t know enough about the virus to say with certainty how long immunity lasts. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, is optimistic, predicting “a few years” of durable immunity. Others aren’t so sure. “My guess is that the protective immunity will last at least three months—that’s the worst-case scenario,” says Peter Openshaw, professor of experimental medicine at Imperial College London. “It’s likely to last much more than that—between one and five years—but until that time has passed, we won’t know for sure.” Researchers in countries including Germany and Italy are starting projects to study the antibodies of hundreds of thousands of people to see how long immunity lasts and map out where the virus has been lurking.

The U.K. has trumpeted antibody testing as a solution but struggled to get it off the ground. British scientists trying to validate thousands of test kits have found them unreliable. If the U.K. wants to introduce so-called immunity bracelets, it will need to be able to do antibody testing on a mass scale, which is only possible with accurate, rapid home kits—and those could take months to develop, scientists say. (U.K. Prime Minister Boris Johnson was hospitalized with Covid-19 on April 6.)

So far, there’s been less talk about formal immunity certificates in the U.S., which is only beginning to push antibody testing. On April 7, New York Governor Andrew Cuomo said his state has developed an antibody test. The Food and Drug Administration granted its first emergency use authorization on April 1 for a rapid antibody test using a finger-prick blood sample, developed by Cellex Inc. It cautioned, however, that the test shouldn’t be used as the sole basis for diagnosis. The U.S. Centers for Disease Control and Prevention has started blood testing for antibodies on people who live in Covid-19 hot spots who never had symptoms, using representative samples of the population to gauge how many cases have gone undetected.

Another caveat: Testing positive for antibodies could mean you’re still infectious. People develop antibodies at the end of the first week, when they can still infect others, Charité’s Volk says. Without symptoms, there’s no way to know whether people are continuing shedding the virus or have recovered unless they take a swab test.

Even with all the drawbacks, antibody testing, whether it results in immunity certificates or not, could help politicians plot their way out of mass lockdowns. “It’s important to understand how the virus infiltrated society—how random or how clustered it is—to make political decisions,” Volk says. “If we have hot spots, maybe you keep them closed for another couple of weeks and open less-infected regions. But it’s too early to give you an immunity passport to let you do what you want.”

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