By Rebecca brown, Julian Savulescu, Bridget Williams and Dominic Wilkinson.

There is significant debate about whether or not ‘immunity passports’ are a viable tool to use in responding to the current COVID-19 pandemic. Much of this has focused on the lack of a sufficiently reliable antibody test, and uncertainty about the immune status of individuals recovered from COVID-19.

Modelling from LSHTM at the beginning of the UK outbreak estimated that an unmitigated epidemic would result in 250,000 – 470,000 deaths in the UK. Similar work at Imperial College put the expected deaths at around 510,000. In order to prevent such vast numbers of deaths, lockdown policies have been adopted in the UK and numerous other countries.

Such lockdown policies have huge social and economic costs with people losing their freedom, prevented from contact with loved ones, and sometimes losing their jobs. They also have significant health costs to delayed or inadequate treatment of patients with non-COVID-19 illnesses. Suppressing the pandemic through lockdown leaves the majority of the population susceptible to the virus, meaning that it is very difficult to ease lockdown restrictions without triggering further outbreaks.

Immunity passports have been proposed as a way of certifying that holders are likely to be immune, and thus unlikely to be at risk of themselves getting COVID-19, and at much lower risk of passing the virus on to others. People with immunity passports could be permitted greater freedoms – perhaps to return to work, visit friends and family, and engage in more leisure activities. As well as restoring personal freedoms, this may also help to reduce the burden of the epidemic on the population.

Many are worried that serological tests are currently too inaccurate to reliably identify those with antibodies to COVID-19. They also worry that we do not yet know if the presence of antibodies in blood plasma is a good indication that someone has long term immunity and will not become reinfected if exposed to the virus. The UK government has repeatedly stated that ‘an unreliable test is worse than no test’. This misleads people into thinking this is purely a scientific, rather than ethical, issue. Ultimately what level of reliability we accept depends on weighing up different values.

The issue of reliability is often framed in complex medical terms like false positives and negatives. These can obfuscate the real ethical issues. False positives (having a passport yet being susceptible) and false negatives (being denied a passport despite immunity) are inevitable, but their existence alone does not undermine the usefulness of this approach. The frequency of false positives can be reduced by selectively testing individuals most likely to have had the disease. The harms of false positives can be mitigated by selectively providing passports to those for whom infection is less risky (young people without pre-existing conditions). These risks must be weighed against the benefits of passports to those who are rendered unemployed and socially isolated by lockdowns, as well as benefits to society at large if others’ – particularly key workers’ – immunity status can be estimated. Even if we are not certain that people are immune, the benefits of restoring their freedom may be worth the risk that they remain susceptible.

We must also judge the risks of passports in light of the alternatives, which at this stage may be full lockdown restrictions for everyone for months or years. Immunity passports should not be expected to act as a ‘panacea’, nor dismissed for not being one, but as one tool amongst many available. We may, yet, require more detailed understanding of immunity post-infection, and more reliable testing methods. Time and science will provide a clearer picture of these, and it is useful to begin our ethical assessments in advance.

Such assessments must consider where the burden of proof lies in issuing immunity passports. To do this we must look at the ethical importance of things like civil liberties and fairness. Currently, almost everyone in the UK is subject to severe restrictions of freedom. This is justified on the basis that their free movement puts at risk their own and others’ health. But for immune individuals this is not the case, and an alternative justification for restricting their freedom must be provided.

Potential justifications are available: it could be too costly to implement an immunity passport scheme; it could undermine solidarity amongst the population if some are permitted more freedom than others; or it could be unfair to those still susceptible and unable to leave lockdown. We critique these considerations at greater length in our paper (Brown et al under review). But the force of these arguments – and whether they are ultimately taken to justify a refusal to restore the freedom of those who are immune – must be balanced with a proper acknowledgement of the violation of people’s ordinary civil liberties that lockdown involves.

The emphasis of the discussion around immunity passports so far has been on whether their introduction is a good idea, and their use justified. This could be the wrong way to look at the question. Instead, perhaps we should ask whether we can justify not using them.

Competing interests: None declared.

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