key: cord-0974470-25txjpv4
authors: Greely, Henry T
title: COVID-19 Immunity Certificates: Science, Ethics, Policy, and Law
date: 2020-05-28
journal: J Law Biosci
DOI: 10.1093/jlb/lsaa035
sha: f061f6dd181e3826ed10d127465d35f44986acde
doc_id: 974470
cord_uid: 25txjpv4

There is much discussion of adopting COVID-19 immunity certificates to allow those proven to have antibodies to the SARS-CoV-2 virus that causes COVID-19 to resume normal life and help restart the economy. This article points out issues that must be considered before adopting any such program. These issues fall into six categories: the uncertain science of COVID-19 immunity; the questionable quality of COVID-19 antibody tests; practical problems with issuing such certificates; deciding how the certificates might be used; and ethical and social issues they would raise, especially fairness and self-infection; and potential legal barriers. It does not ultimately take a position on whether some narrow COVID-19 immunity plans should be adopted, concluding that the answer depends on too many currently unknown conditions. But it seventh part makes recommendations to decision-makers who might consider implementing such programs.

But it seventh part makes recommendations to decision-makers who might consider implementing such programs.

To buy a drink at a bar, you may be asked to show a document to prove your age. What if you had to prove you were immune to COVID-19 1 -in order to go to work, to use public transportation, to go to a concert or sporting event...or to go in a bar to buy a drink? The idea of immunity certificates,‖ -immunity passports,‖ or -immunity licenses‖ is being discussed with increasing seriousness in the U.K. 2 , Italy, 3 Chile, 4 Estonia, 5 and the United States. 6 It initially 1 The current pandemic disease caused by a novel coronavirus is now often referred to as -COVID‖, -Covid‖, or -covid‖, with or without a --19‖ attached. (The --19‖ refers to 2019, the year it was first identified, and does not imply there were COVIDs 1 through 18-there were not.) This is a shortened version of -Coronavirus disease 2019‖. It is also sometimes referred to as the -novel coronavirus disease‖ or just -the coronavirus.‖ This article will refer to it as Adam Bienkov, The UK Plans to Issue Coronavirus ‗Immunity Passports' So People Can Leave the Lockdown Early, BUS. INSIDER (Apr. 3, 2020 1:15 AM), https://www.businessinsider.com/uk-plans-coronavirusimmunity-passports-so-brits-can-leave-lockdown-2020-4. This article begins what will need to be a much longer and deeper discussion-if the future develops along certain paths. It proceeds in six parts. The first five of those parts argue that immunity certificates come with major problems. I start by reviewing some of the scientific questions of immunity to COVID-19 and, second, look at antibody tests. The third and fourth parts discuss some of the practical problems they raise, first in issuing COVID-19 immunity certificates and then in how such certificates might be used. (Although not scientifically or ethically exciting, and hence thus far rarely discussed, these may turn out to be the biggest barriers to the implementation of such immunity certificates anytime soon.) Only then, in the fifth and sixth parts, I begin to consider the ethical and social issues stemming from immunity certificates and possible legal barriers to their adoption and use. The last part shifts gears.

Although I believe such certificates should not be implemented now, I end with seven suggestions for decision-makers considering them in a less uncertain future.

The article raises far more questions than it answers, but it raises questions that will need to be answered, carefully and rigorously, if immunity certificates are to be tried. I hope laying out the issues may help others discuss and debate such answers.

But, first, I need to provide an important warning. Our knowledge about all aspects of this pandemic is changing rapidly and it could well be that everything we know is wrong. 9 This article is based on what seemed to me the best information available at the time it was initially submitted, April 20, 2020, as updated as of the time of its last revision, May 25, 2020. Some of its -facts‖ will almost certainly be wrong whenever the -now‖ is when you read it. Caveat lector!

The human immune system is extraordinarily complicated. Over 30 years of working in law and the biosciences, I have concluded that human neuroscience is orders of magnitude more complex than (very complex) human genomics. The human immune system is actually a combination of a variety of different approaches, which sometimes are lifesaving…and sometimes, when they over-react, are deadly. What follows is an enormously oversimplified depiction of just one part of the immune system, but it should be useful.

On the other hand, if you are not interested in the science behind immunity questions, or already know it well, you can skip to the next part. You just need to know that we do not know whether people infected with COVID-19 have any immunity, have probably but not 100 percent immunity, or have partial immunity that mitigates symptoms but does not prevent reinfectionand for how long any of the various kinds of immunity last.

Of the immune system's many parts, the part that is of most concern in this context is Immunoglobin G (IgG). IgG is an antibody, a molecule that circulates in the blood, recognizes a specific -non-self‖ virus or cell by some of its molecules (called -antigens‖), binds to them, and leads to a variety of attacks on the invading virus or cell. The human immune system makes many kinds of antibodies but various forms of IgG make up about three-quarters of the antibodies found in blood. Some of those form will last a lifetime. (IgG is also found in nonblood fluids outside of cells, such as lymph). It is part of what is called the -humoral immune system.‖ 10

White blood cells known as -B‖ cells produce so-called -B-cell receptors.‖ The receptors lead the B cells to bind to specific molecules or molecular structures found on or as a result of an invader. These molecules or molecular structures are known generically as -antigens.‖ When these B cells encounter -their‖ antigens, the B-cell receptor binds to it and the B cells multiply

and change into what are then called -plasma cells‖.

These plasma cells release IgG and other antibodies. They ramp up to enormous production of IgG in the days after an infection-a -foreign‖ invasion. Each individual plasma cell produces several thousand antibodies per second. After the infection has passed, production decreases markedly. But some of the B cells that specialized in the particular antigen found on that particular invader can survive for decades. If the body detects that same antigen again on an invader, those cells can quickly lead to massive production of antibodies. These cells are known as -memory B cells.‖ Memory B cells form one of the bases for our continuing and often lifelong immunity to some diseases, such as measles. Unfortunately, this immunity does not last long for

all disease-causing entities. Some of them, like the various human influenza viruses, change so rapidly that last year's antibodies will not recognize this year's influenza. For others, IgG production and the memory B cell stockpiles are weak or quickly lost.

When people are infected with SARS-CoV-2 (the virus that causes COVID-19), 11 their immune systems seem generally to produce IgG that spots and binds to specific proteins on that virus. 12 This process takes several days. The exactly time range is not clear but it appears to be about seven to ten days from infection to production of significant amounts of the relevant IgG. 13

The immune system produces another kind of antibody, called Immunoglobin M (IgM).

This appears more quickly but is not nearly as specific. IgM can bind to many antigens on different kinds of invaders and can lead, again through different paths, to their destruction. IgM appears very quickly after infection but also fades away quickly. For SARS-CoV-2 the early 11 This is the name given the virus that causes COVID-19. It is sometimes referred to as -the novel coronavirus‖ or -the virus‖ but this article will use its formal name. SARS-CoV-2 is a species of -coronavirus,‖ a term that refers to a large family of viruses that infect humans and other animals. The name comes from the fact that they have spikes that, through an electron microscope, look like a -crown,‖ which in Latin is called a -corona.‖ At least seven species of coronavirus are known to infect humans. Four of them cause common colds; three cause more serious illnesses. The virus that causes COVID-19 genetically very similar to the coronavirus that, in 2002-03, caused a deadly epidemic of Sudden Adult Respiratory Syndrome (SARS). As a result, the virus causing COVID-19 has been named SARS-CoV-2 (and the virus that causes SARS has had a --1‖ added to its name. 

In other cases, the antibodies are either too weak to prevent a new infection or dissipate or even disappear in a short time. And in still other cases, like HIV-infection, the infection, and the patient's ability to infect others, will persist even in the face of robust antibody production.

These different outcomes may be functions of the particular virus involved or may stem from a patient's other conditions. The immune system weakens as people age; the elderly may no longer be able to mount a strong immune response to a known antigen. Similarly, people with immune systems weakened by some diseases or by some treatments, such as chemotherapy or radiation therapy for cancer, may not be able to fight off the previously seen invader. The same may be true of people taking immune suppression drugs as a result of some organ transplants or as treatment for some diseases caused by an overactive immune system.

Some viruses managed to hide successfully from the immune system, going dormant for a long time before recurring. The virus that causes chicken pox, Herpes zoster, can do that, often re-emerging decades later as the painful condition called shingles.

Note well that immunity can be weak in various ways. It can protect fewer than all of those infected, it can protect them for only a limited time, it can provide the limited but often valuable protection of weaker symptoms-or it can do any combination of the above. There seems to be no particular reason to expect SARS-CoV-2 to pose extreme problems for human immune systems but, at this point, we just cannot know. We have, at most, six months of experience with this virus in humans. We also have some experience with other coronaviruses, including those responsible for about 10 to 15 percent of Americans' -common colds.‖ 21 Some of those other coronaviruses lead the body to produce antibodies, and immunity, for a few months or a year.

As to SARS-CoV-2 itself, here's the little we currently know about it and immunity. 22

The best test of immunity is whether the virus can re-infect an already recovered patient. The points below, and more, are summarized in this nice review: Andrew Joseph, Everything We Know About Coronavirus and Antibodies-And Plenty We Still Don't, STATNEWS (Apr. 20, 2020), https://www.statnews.com/2020/04/20/everything-we-know-about-coronavirus-immunity-and-antibodies-andplenty-we-still-dont/. There is no strong evidence that infection with SARS-CoV-2 or a diagnosis of COVID-19 fails to confer at least some immunity, in at least most of the people it infects. But there is also no strong evidence that it does, and, if so, how strongly and for how long. One respected epidemiology, Marc Lipsich of Harvard University, recently summed up his view:

After being infected with SARS-CoV-2, most individuals will have an immune response, some better than others. That response, it may be assumed, will offer some protection over the medium termat least a yearand then its effectiveness might decline. 32 We may get a clearer answer soon, as the specific papers, or pre-prints of papers, cited here are supplemented, or supplanted, by others. (Of course, we can never know whether, for example, immunity lasts for five years until at least five years from the first cases.) But while POST (Apr. 7, 2020) 

the uncertainty persists, it is vitally important to the question of immunity certificates. If people receive certificates granted on the basis of positive antibody tests but they are not, in fact, immune, not only can they be (re)infected but they can infect others.

But let us assume SARS-CoV-2 infection provides some degree of immunity for most of those infected, probably for at least one year, before declining. Then how could we test for that immunity?

The best way would be to test people directly for SARS-CoV-2 antibodies. ( (May 2, 2020) . https://www.governor.ny.gov/news/amid-ongoing-COVID-19-pandemic-governor-cuomo-announces-resultscompleted-antibody-testing.

But…no test is perfect. For example, physicians and researchers are increasingly suggesting that as many as one-third of the positive tests for viral RNA may be false negatives. 40 Just like viral RNA tests, antibody tests are imperfect. Some will detect antibodies that do not exist (false positives), others will miss antibodies that do exist (false negatives). False positives may be a particular problem here, as sometimes the tests might signal positive for SARS-CoV-2 either completely inaccurately or when they are really detecting antibodies to the cold-causing coronaviruses.

Although the U.S. FDA has not -approved‖ any such tests, it has allowed some to be used and other tests have been deployed in other countries. Their accuracy is deeply suspect. For example, the U.K. had planned to embark on a major survey of antibody rates in its population. It contracted for 17.5 million antibody tests, from nine different firms.

The government is working with nine companies that have developed coronavirus antibody tests, which screen for whether someone has recovered from the disease and is likely to be immune. 2020) , https://www.statnews.com/2020/03/31/COVID-19-overcoming-testing-challenges/ (noting there is a growing concern that tests are imperfect, and poor sample collection could produce false negatives). It is thought that many of the false negatives are a result of bad samples; patients do not like to have swabs pushed deep into their throats or up their noses and the swabs may not penetrate far enough to find virus-laden mucus.

Downing Street confirmed on Monday that -no test so far has been proved to be good enough to be used‖ and said it was working with the companies to improve their quality. 41

How accurate are antibody tests in use in the U.S.? The FDA classifies tests used to detect antibodies as medical devices and claims regulatory jurisdiction over them. In theory it will not allow them to -enter into interstate commerce‖ unless they have been shown to be safe and efficacious. The practice is a more complicated.

For decades FDA has allowed medical laboratories to use tests FDA has not approved through the so-called Laboratory Developed Test (-LDT‖) exemption. It is not in the FDA's statutes but the agency uses its enforcement discretion to not meddle in a well-run and regulated field. These laboratories are licensed by the states, run by pathologists, and generally accredited by the College of American Pathologists. How well they perform the tests is also regulated by a federal statute called CLIA (-the Clinical Laboratories Improvements Amendments Act of 1988‖ See an excellent explanation of EUAs in Erika Lietzan, Emergency Use Authorizations, OBJECTIVE INTENT (blog) (Feb. 24, 2020), https://objectiveintent.blog/2020/02/24/emergency-use-authorizations/. As Professor Lietzan notes, the EUA provisions also put some restrictions on LDTs. FDA said that once the Secretary of the Health and Human Services had declared an emergency about a particular disease, a necessary prerequisites for any EUAs for that disease, qualifying laboratories would have to get an EUA even for what would otherwise be LDTs. On February 29, she notes, FDA weakened that requirement to allow labs certified for -high complexity testing‖ to use their own LDT for a COVID-19 test as long as they had applied for an EUA, whether or not one had been granted. 43 Id.

does not intend to object to the distribution and use of serology tests to identify cheap, and widely available, blood will still need to be drawn. Health care workers will be needed-and they will need personal protective equipment. In the U.S. medical world at the time of writing, both trained health care personnel and, even more, personal protective equipment are in short supply. Widescale testing may be impossible for these apparently mundane reasons--for want of a nail‖.

Some firms are trying to develop antibody tests that could avoid this problem. Some firms have been selling them (including the firms who -sold‖ tests to the U.K. government.

These tests would be able to analyze a very small quantity of blood accurately, thus allowing an accurate test if the subject himself produces a finger prick's worth of blood. The idea has been called -Antibody on a Stick‖ and operates rather like a home pregnancy or HIV test. A manufacturer puts on a small plastic strip a protein or protein fragment that the sought-after antibodies will stick to if blood is smeared on it. If the antibody attaches to the strip, other chemical reactions will make the strip change color. It seems likely but not certain that this method, even though given a bad reputation by the Theranos fraud, can be used successfully in this context. If so, it would alleviate many of the logistical problems with antibody testing (but import some new ones, discussed below).

Let's assume that we think a positive antibody test is powerful evidence that someone cannot acquire or transmit the infection. And let's assume that we have good antibody tests-not perfect, but -good enough‖. Are there issues about using antibody tests to issue COVID-19 immunity certificates? You will not be surprised that my answer is -yes,‖ for both honest and dishonest certificate issuers and applicants.

First, who will issue the certificates? Gas and Electric Corp. v. Public Service Commission, 447 U.S. 557 (1980) and the extensive -commercial free speech‖ jurisprudence that has followed. I am not attempting, in this piece, to take a position on-or even to assess the strength of-such this argument or some of the others mentions (notably the Dormant Commerce Clause). I am just trying to point out some non-frivolous issues.

convinced of a person's immunity based on an antibody status ascertained by an unapproved test or a dodgy (or foreign) laboratory, barring legislation, would anything prevent that? (We will come back in the next section to the question of the powers certificates might confer; for now we are just concerned with their issuance.)

But there is another issue. Antibody tests are not the only evidence that might be used to infer that someone is immune to SARA-CoV-2. Given enough data (or enough assumptions) about the generation of IgG COVID-19 antibodies, one might, perhaps not unreasonably, presume that anyone who has had the disease is now immune and therefore issue COVID-19

immunity certificates to them. That might even end up being scientifically justified-although it is clearly not justified yet.

Even assuming that inference is right, how will we know whether an applicant for a Departments of Motor Vehicles come to mind, although not necessarily in a good way. Whatever agency is given the task, how long will it need to work out protocols, procedures, and regulations, as well as the expertise to do a good job? And how long will people, eager to get their -Get Out of Jail Free‖ cards, wait? Actually, will the certificates be free? If not, they will impose some financial burdens, small or large, that will fall disproportionately on the poor.

Here's another question-whoever issues them, what should the certificates -look like‖?

If they are just a doctor's letter or a form from a lab, they might be easily forged or borrowed from the true holder for use by someone else. Perhaps they should be like driver's licenses, but, as many underage kids seeking alcohol and others figured out, fraudulent drivers licenses are not that hard to buy or to make. We could require more serious identification methods, like fingerprints or retinal scans. Or we could do an on-line system: anyone claiming immunity would provide some kind of personal identification and would then have the existence of certified immunity checked through an on-line database. Of course, that way a computer knows every time and place your immunity has been checked -perhaps every restaurant or bar you've

been to. The privacy concerns are not as great as those involved in proposals for automated quarantine, isolation, and contact tracing, but they are not small. 53

Now consider one last question about (honest) certificates from legitimate certifiershow long should they last? If the basis for issuing the certificate (antibody levels, past documented infection, or something else) is known to last, at full strength, for a lifetime, then the certificates can last for a lifetime. But we don't know that-and, in fact, can't know that for a long time (quite literally, for a lifetime). Should these certificates be like drivers' licenses that must be renewed every few years? And, if so, for how many years? At some point, if we know the immunity is not lasting, we may know how often the certificates would need to be renewed.

But, at the start, how long should they last? One year, two years, three? We must, of course, hope that prevention or great easy treatments or effective vaccines will come along within a short time and make the whole question moot-but we cannot assume that. Someone has to set a reasonable initial term for the certificates.

Then there is another problem: outright fraud. If immunity certificates provide real benefits, people are going to want them. Some people are going to want them enough to lie and

cheat. An entire black market industry might spring up to meet this demand-though, more likely, those who already provide false social security cards or driver's licenses may expand their offerings. 53 Edlin and Nesbitt have recognized the serious problems of potential fraud and are drafting a proposal for using a centralized database to resolve some of the issues. Email from Bryce Nesbitt, April 15, 2020, on file with author. As far as I know, they have not yet published this.

Assume a person shows up applying for an immunity certificate with a document that purports to be a test result saying -Henry T. Greely‖ has a qualifying level of SARS-CoV-2 IgG antibodies. How does the certificate issuer know the document is authentic instead of forged?

Computers, software, and printers can make fraud easy. Unless we require the lab reports to be on counterfeit-proof paper, fraudulent documents will be a problem-bought on the black market but also from some -do it yourself‖ forgers.

Henry T. Greely. How hard do we make him prove it? A driver's license (which may not be authentic)? More? Less? Part of the answer to that will depend on the incentives of the person providing the certificate. Having a reputation for low standards could easily lead to more business-and, of course, frank bribery is possible. A newly established industry, or newly established government certifying offices, may well lack the kinds of controls and bureaucratic oversight that reduces fraud and corruption in more established contexts.

Remember-the stakes with immunity certificates may be very high. If a person who is not immune has an immunity certificate-because of error, fraud, or other reason-that person might contract the disease, with or without symptoms, and pass it on to others. 54

It appears that about 40 percent of those infected with SARS-CoV-2 never show any symptoms but have the same viral load, and, presumably, the same ability to infect others, as those with symptoms. See Eric Topol, https://twitter.com/EricTopol/status/1252412650790678529 and the sources he cites. (The absence of some symptoms, such as coughing and sneezing, however, may reduce to some extent how contagious the asymptomatic carriers are.) When I was a freshman at Stanford, long ago in a galaxy far, far away, the legal drinking age was 21 in California. Two people in my dorm made and sold fake driver's licenses. They had a big poster board on which they had printed what purported to be an Iowa driver's license. The poster had a rectangular hole. The purchaser would put his head behind the hole, they would take a Polaroid photo 55 and, after laminating it, hand it over as a fake id. One of the purchasers of a fake Iowa license later told me that, at one local student bar, the bartender had looked at him, said -you spelled license wrong‖ (-lisence‖), but sold him beer anyway. The best security measures possible for making -secure‖ immunity certificates will not help if those at the doors who are supposed to demand them instead ignore them.

Polaroid cameras produced -instant‖ photographs (within a minute or less) without requiring developing or printing. See the Wikipedia entry on -Instant Cameras‖: https://en.wikipedia.org/wiki/Instant_camera.

I hope the article to this point has convinced you that COVID-19 immunity certificates raise many questions. But the scientific and practical questions discussed thus far, though very important, are conceptually easy compared with the questions this section discusses, the ethical and social issues as well as the legal issues. This article takes only the quickest and shallowest look at them, but even that should be daunting.

I can see many hard ethical and social issues raised by immunity certificates and I am confident there are many more I am not seeing. In this article, I will focus on only two: fairness and self-infection.

Contemplate a country where, stretching for unknown months or years into the future, some lucky people will be able to work, travel, shop, and entertain themselves freely. Others will be restricted, more or less strictly, from some or all of those activities. The criterion on which this rigorous scheme, akin in some ways to the old South African apartheid, is based is not any kind of merit or positive actions, but, like race or ancestry, something that most people will have had little or no control over-who has, and who hasn't, contracted COVID-19. To many concerned people, immunity certificates will be the key to reopening the country and the economy, and thus limiting the many truly bad consequences of a severe recession (genuinely bad not for stockholders, employees, and almost everyone in the country). For those who have been infected-and who have survived-a COVID-19 immunity certificates would be the key to

a return to a normal life. But for those who are not immune, the certificates lead to gross and deeply unfair discrimination. And they will say -it's not fair!‖ Of course, they will be right. It will not be fair. It may make sense in terms of protecting people and their societies from the worst ravages of SARS-CoV-2, but it will not be fair.

Unfairness exists in many aspects of the world and we usually accept it, either because we have no choice, because we are used to it, or because it clearly leads to better outcomes. To what extent and for how long would COVID-19 immunity certificates be tolerated by Americans? Fraud and outright disobedience would grow. It probably would not reach the stage of significant active unrest. More likely, the political pressures for watering down the certificate requirements, or for softening or removing the restrictions that the certificates could overcome, would soon prove irresistible. Whether ethical or not, I strongly suspect that the social and political effects of a substantial immunity certificate program would be sustainable for only a limited time.

The second problem is harder, both ethically and practically. If COVID-19 immunity

certificates are useful and if vaccination is not yet a way to obtain one, some people will be tempted to become infected in order to obtain SARS-CoV-2 antibodies and an immunity certificate-if they survive. 

If competent adults are fully informed of the risks, why shouldn't we let them take those risks? Often we do-we let people ride motorcycles. Sometimes we don't-we don't, in most states, let them ride motorcycles without helmets. Ethical theories again will disagree among themselves; the answers ultimately are political and cultural.

But the party scenario is not the same as the motorcycle helmet. To a large extent, if home infection testing becomes available, which many are seeking because of its advantages in identifying COVID-19 cases, those who learn through a self-administered home test that they are infected could help others become infected before any authorities in charge of their isolation know they are tested positive.

The complexities of the various forms of possible immunity certificates and their intersections with the laws of different U.S. jurisdictions are enormous and so are the questions they raise. Perhaps ironically-for an article published by a law professor in a law journal-this section will not try to answer any of them, but, instead, will try to point out four of the issues that seem both largest and most obvious: the authority of the federal government, the legality of executive as opposed to statutory actions, independent constitutional bars to immunity certificates, and statutory obstacles to them.

One big question is authority, particularly that of the federal government but also of the states and of private actors. Under the Constitution, the federal government is, at least in theory, one of only limited and enumerated powers. COVID-19 immunity certificates might be used for things that seem clearly within the scope of federal power such as interstate methods of transportation. Others are the kinds of local activities that are traditionally regulated by the states

and their subordinate local governments. One might imagine the federal government regulating airplane travel but states, counties, or cities regulating buses or restaurants. 60 The possibilities for inconsistency and confusion are great.

The most likely source of a broad federal power would the Interstate Commerce Clause, but we still do not know just how far it reaches, other than that it does not reach everywhere: to violence against women, 61 to gun sales near schools, 62 or to forcing people to buy health insurance. 63 The federal government might, for example, assert it to require immunity certificates at, say, restaurants and other public accommodations. It would have precedent in its favor though its success could not be guaranteed. 64 This is primarily an issue for the federal government. State governments have the broad powers of sovereignty, including particularly the so-called police power. They may be constrained by their own constitutions or by federal law but their underlying authority exists. 60 One might expect to see some governments use COVID-19 certificates in pursuit of other goals. Just as some states have used the COVID-19 emergency to forbid abortions as -non-essential medical care‖, a government might strongly require the use of certificates for behavior of which it disapproved, from questionable massage parlors to head shops-and possibly try to make the identity of the certificate users public. 

Private actors, at least if they are competent adults, typically have no -authority‖ issues-they can do anything that is not forbidden. (Effective limitations on the actions of corporate -persons‖ as -ultra vires‖ or beyond the powers conferred upon them by the chartering authority or their own foundational documents have largely disappeared.)

With regard to governments (though not individuals) action on immunity certificates will depend not only on which government but acting under what authority. A certificate plan laid out in recently passed legislation is different from one depending on executive action based on an assertion of emergency powers, whether based on broad statutes or claimed as inherent.

The cleanest solution, at any level, would be new legislation. New legislation, at either the federal or the state level, avoids a host of possible legal questions about whether the immunity certificates are legally authorized. It also would avoid some questions of legitimacy to the public. Although not impossible, it is harder to rail against a legislative dictatorship than one imposed by a governor or President. Fresh legislation may well increase public support for the measure. It would also afford at least the opportunity for committee hearings, debate, deliberation, and other mechanisms for raising (and sometimes resolving) problems with the proposal. And it would, unless a legislative majority were to ram the legislation through, allow stakeholders to have a voice in the eventual plan, and thus, perhaps, to accept it better. 66

Note that some of those stakeholders will be businesses eager to sell products or services related to immunity certificates. This potential market has already been noticed and lobbying from such firms should be expected. See Sue Halpern, Immunity Passports and the Perils of Conferring Coronavirus Status, THE NEW YORKER

All of these procedures provide some substantial potential benefits in the substance and acceptance of legislation. They can also make for a nightmare of delay and sabotage of any bill.

This seems particularly worrisome in jurisdictions where the executive and one or both of the chambers of the legislature 67 are not controlled by the same party. It is almost impossible for me to imagine any circumstances where, for example, President Trump, a Republican-controlled Senate, and a Democratic House of Representatives could agree on a COVID immunity certificate statute.

An alternative is for the executive to claim inherent authority to act in the case of an emergency. At the federal level, the precedents are mixed. President Lincoln claimed the emergency power to suspend the writ of habeas corpus during the Civil War; Chief Justice Taney held that he had no such power but only in an opinion in a lower federal court. 68 Korematsu v. United States, 323 U.S. 214 (1944) . In 2018 both the Opinion of the Court and two dissents stated that Korematsu had been wrongly decided, but the concern was not the source of the President's authority but how it was used in that case. Trump v. Hawaii, No. 17-965, 585 U.S. ___ (2018) , 70 Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579 (1952) .

There is a third way. Congress over the years has passed many statutes that confer various powers on the President or other Executive branch officers in the event of a declared -national emergency.‖ The Public Health Services Act is the most apparently relevant here. 

In statutory law, the most attractive source of legal arguments against such actions appears to be laws barring discrimination based on disability-most prominently (but not solely)

the Americans with Disabilities Act (-ADA‖) at the federal level and a wide range of varying state anti-disability discrimination statutes. These bar governments and private parties from discriminating against people for reasons that involve health. Employers cannot (generally) discriminate against blind job applicants, public accommodations like restaurants or concert halls cannot discriminate against people in wheelchairs, educational institutions cannot discriminate against the hearing impaired.

On closer examination, though, their application is very unclear. I will focus on the ADA, in the full recognition that different language or different interpretations in state statutes (or perhaps in other federal statutes involving discrimination based on disability status, such as the Rehabilitation Act) might lead to different results.

The ADA bans much discrimination against people with disabilities. Someone is a person with a disability if he or she has (A) a physical or mental impairment that substantially limits one or more major life activities of such individual;

(B) a record of such an impairment; or (C) being regarded as having such an impairment… 77

In Bragdon v. Abbott in 1998, the U.S. Supreme Court placed major emphasis on the -impairment‖ requirement as a perquisite. 78 In deciding whether an asymptomatic HIV infected person could be classified as disabled under the ADA, it ruled that there was an impairment even before symptoms because the person's immune system was under attack. But people with immune systems do not have antibodies to SARS-CoV-2 because that virus hasn't infected them, although their systems are -impaired‖ in a deep way-they don't work the way we would like them to work-seem unlikely to be viewed as having a physical impairment.

On the other hand, the third prong of the definition, -being regarded as having such an impairment,‖ might fit. It apparently was intended for situations where people thought or assumed incorrectly that someone had a disabling impairment. One of the examples discussed at the time (the late 1980s, near the height of the U.S. AIDS epidemic) was a man who appeared to be gay and was assumed to be HIV positive and was so treated. That was someone incorrectly regarded as having a characteristic that would clearly (at least, -clearly‖ after Bragdon v. Abbott) be an impairment, not someone regarded as having something that was -incorrectly‖ viewed as an impairment. There are, no doubt, law review articles that could be written on the application of the -regarded as‖ prong to this situation based on statutory history, regulatory language, case law, and other sources. This is not one-for present purposes, I will just say that its applicability is unclear.

ADA law has other twists, one that might favor susceptible people (if they were classifiable as having a disability) and one that might cut against them. The beneficial one is the 78 Bragdon v. Abbott, 524 U.S. 624 (1998) .

reasonable accommodation requirement in the ADA's treatment of employment discrimination:

an employer may not discriminate against a person with a disability who could discharge the essential duties of the job if given -reasonable accommodations.‖ For someone not immune to SARS-CoV-2, that might mean working from home, in an isolated workspace, with a N95 mask and other personal protective equipment, or some other change. Title III of the ADA, dealing with public accommodations, requires those places to make -reasonable modifications‖ but the emphasis under that section has been on architectural changes; I do not know whether it might apply to a non-immune restaurant patron requested admission without a certificate but with secluded seating and, for example, an immune waiter.

On the other hand, the ADA also includes a -direct threat‖ provision, which allows employers to discriminate against people who pose such a threat. The ADA regulations provide that -The term ‗direct threat' is defined as ‗[a] significant risk of substantial harm to health or safety of self or others that cannot be eliminated or reduced by reasonable accommodation.'" 79

The Equal Employment Opportunity (-EEOC‖) has already issued guidance that someone who is infected with SARS-CoV-2 poses such a direct threat. 80 

cover them? Perhaps-in some states or in some contexts. But I doubt that any broad, general protection against the application of immunity certificates will be found to exist.

Are there legal barriers to immunity certificates? Maybe, in some situations. Many devils lurk in those details. But, although it may be possible, I think it unlikely that existing law provides broad protection against discrimination for those who would not qualify for such certificates.

To me, the case for immunity certificates is not powerful, mainly because of the six classes of problems discussed so far. Scientifically, the existence and extent of SARS-CoV-2 immunity is unclear, as is the quality of antibody tests. Practically, how to issue the certificates and for what purposes raise hard issues. Ethically and socially, problems of fairness and selfinfection are rampant. And many potential legal barriers exist.

On top of all of these, add the relatively unimportance of such a program while the number of immune people remains low. Even if everyone who has had a case of COVID-19 has sufficient immunity to justify granting a certificate, at the highest current plausible estimate at the time of writing, that is probably not more than five percent of the U.S. population. If you are interested in -re-starting the economy,‖ is there much point to creating a system of immunity certificate that allows five percent of employees to return to work, five percent of customers

return to restaurants, and five percent of sports or music fans return to stadiums, arenas, or concert halls?

But that percentage seems unlikely to remain low forever, and, even while it does, such certificates might be useful in some contexts, particularly in those where the functions are important and substantial personal contact is involved. Some good candidates include attendants in nursing homes, nurses and doctors in COVID-19 wards of hospitals, police and fire fighters, lifeguards, or others whose (important) work makes highly effective protective measures difficult or impossible. The issues raised in this article lead me to offer seven specific points of advice to anyone thinking about an immunity certificate program.

Congress or the federal executive branch, especially during a Presidential election year (and perhaps in its aftermath). State action would also avoid some difficult questions about the reach of federal authority; those areas where the federal government has exclusive jurisdiction are not likely to be crucial to such state plans. Local conditions, in the epidemic, the economy, or the culture may make local or regional variations useful, plus the states may serve as the much- It is unlikely that legislation will be able to provide the detailed answers needed for such a plan as the facts on the ground change frequently (more likely, constantly). Sone kind of regulatory body will need to be empowered to issue regulations to cover many details-and to change those regulations as necessary. States may want to consider whether their current

requirements for administrative action (their equivalents to the federal Administrative Procedures Act) will be adequate for frequent technical changes.

Second, those state programs need to define, very carefully, what evidence will be sufficient to allow someone to receive an immunity certificate. The programs should be clear whether antibody tests are needed or whether evidence of past but not present infection will suffice. They should specify which kinds of tests will be acceptable, either by reference to categories (e.g., -FDA-approved tests for SARS-CoV-2 IgG‖) or perhaps specific manufacturers or laboratories. They should be specific, where appropriate, on particular test results. Thus, they might require an antibody test to show at least a certain level of particular SARS-CoV-2 IgG antibodies at a given time after the likely date of infection. And they should detail what proof will be required that the proffered evidence is authentic: original versions of laboratory tests (whether received on paper or electronically), a direct confirmation from the relevant laboratory or medical facility, an affirmative answer from a trusted database set up to store such test results.

Nothing can completely eliminate the chance of fraud, but careful steps should be able to minimize it. This level of detail is an example of what probably needs to be provided by regulation or executive order rather than being enshrined in harder-to-change legislation.

Third, the program will need to define what the immunity certificates are good for. I suggest that they define three broad categories-activities (if any) for which an immunity certificate is required, activities where decision-makers such as business-owners or local governments are allowed to require immunity certificates, and activities for which immunity certificates may not be required. The last group might include, for example, interactions between parents and (minor?) children, buying groceries, or some form of voting. The enabling provisions, whether statutes or executive orders, probably cannot contain all the possible activities. They can set out the ideas behind the categories and provide some common -including but not limited to‖ examples, but, again, they will almost necessarily have to give some regulatory entity the power to define them more specifically.

Fourth, the programs will have to worry about how well the activity provisions of the certificates will be implemented. If, for example, nursing homes are only allowed to hire people with immunity certificates for patient care duties, how will that be enforced-especially if both the nursing home operator and the potential employee desperately want to create a prohibited employment relationship? These questions were raised in Section III above; states will need to think about these problems and assure that their programs use reasonably adequate verification measures.

Fifth, depending on how widely and effectively the COVID-19 immunity certificates are being used, states will have to worry about -COVID-19 parties‖-people intentionally trying to become infected so they get a certificate. How big a problem this will turn out to be is deeply uncertain. If only a few jobs or other desirable things (restaurants, travel, sporting events) are closed to people without certificates, few people may think intentional infection makes sense.

The same will be true with more knowledge about the disease: if it turns out that younger people are very unlikely to die, or to become hospitalized, getting infected looks more attractive. If illness rates are higher, or if it turns out COVID-19 has very serious long term effects-on the heart or the brain, for example-getting infected may look worse (at least to those not living

entirely in the present and immediate future). The size of the potential problem is thus unknown, and prone to shift quickly. But it could be a problem, not just for the health of those who successfully become infected but also for those whom they may end up infecting (which in turn depends on the infection testing, isolation and contact tracing system we have in place).

The size of the problem is uncertain. Even worse, the existence of any good solution is unclear. Criminalizing intentional self-infection seems very hard to enforce. Daniel Hemel and

Anup Malani have suggest -bribing‖ people to avoid self-infection through unemployment insurance. 85 This might be a useful solution, at least for self-infection motivated by unemployment instead of, say, a desire to go clubbing, though whether it is politically realistic seems unclear. States will need to worry about this.

Sixth, the programs will have to respond clearly and strongly to changing circumstances, on at least three different levels. At the personal level, it will probably make sense, at least at first, for the holders of these certificates to be retested at some regular interval. We need to renew our drivers' licenses every few years; with basic knowledge about COVID-19 immunity deeply unclear, states may want to require that certificates be renewed after a stated period, based on their bearers demonstrating that they continue to meet the immunity requirements through new testing. At the implementation level, the program needs both to authorize-and to make very clear-that its terms may be changed at any time based on new scientific knowledge.

That may mean allowing more certificates to be issued based on good news about immunity; it may also mean cancelling all such certificates if research shows that there is no good immunity to COVID-19. And, then, at the program level, the system should have sunset provisions. After 85 Hemel and Malani, supra at n. two years, three years, five years, the program should disappear unless the state government readopts it. I generally believe in sunset provisions but the scientific, economic, and cultural uncertainties this pandemic breeds make them especially important here.

Last but not least, states will have to think twice, or three times, about instituting COVID-19 immunity certificate programs. Whether and to what extent they will make sense seems, to me, very unclear, but even beyond the decision to act or not act, how to act will take thought, time, and input from many voices. I have laid out some suggestions that seem to me to make sense, but mine is just one perspective. Many stakeholders, from science and medicine, from business and education, from the general public, and from others will bring different insights into both the framing of such a program and the decision whether or not to adopt it.

The good news here is that the states have some time. The percentage of people who could qualify for an immunity certificate currently is almost certainly very small, in almost all states, as of May 2020, under five percent. The issue will probably become more important as that percentage rises, but states do have some time to reflect, debate, and consider these programs. They have at least several months-but they certainly do not have several years.

Unless, that is, states turn out never to need to address fully the issues of COVID-19 immunity certificates. If a safe, effective, and widely accessible vaccine for SARS-CoV-2 is developed, these issues will largely disappear-largely, but not entirely. The questions then would move to vaccination certificates. Those, at least, should be available to (almost) everyone, but government and society would still have to deal with people who cannot be vaccinated-

newborns, those with compromised immune systems, people with egg allergies, and the like-as well as those who object to vaccination.

Oh, and I do have one last, eighth, piece of advice to institutions considering implementing a COVID-19 immunity certificate program-lawyer up! You may win, you may lose, you may not be challenged, but you will need good legal advice, and lots of it.

Immunity certificates might turn out to be an important part of the other side of the COVID-19

pandemic. But, as with everything in human affairs, they are complicated. Getting the details wrong could do more harm than good. We need to think carefully about them-before adopting them.

Abortion during the COVID-19 Pandemic -Ensuring Access to an Essential Health Service, THE N. ENG

1. States should establish immunity certificates by binding laws, 2. The evidence needed to issue a certificate should be specified carefully, 3. Uses of immunity certificates-requiring, allowing, or banning-should be spelled out, 4. Enforcement and fraud problems (and privacy) need to be taken seriously, 5. Self-infection should be discouraged, 6. Programs need flexibility to respond quickly to changing facts and circumstances

There are some benefits to national (or even, eventually, international uniformity) but I suspect state governments will be better placed that the U.S. federal government to adopt these. They may well be more nimble, and serious than National Governors Association

This discusses the Western States Pact between California, Oregon, and Washington; a Midwestern Alliance of seven states

This term refers to the role helmetless motorcycle riders can play as common organ donors. The term is more often used (inappropriately, I think) to refer to the motorcycles and not their riders. See, e.g., Stacy Dickert-Conlin, Todd Elder, and Brian Moore, Donorcycles: Motorcycle Helmet Laws and the Supply of Organ Donors, 54 J. L. & ECON. 907 (2011).