The ‘International Certificate of Vaccination or Prophylaxis’, better known as the Yellow Card, is essential for entry into more than three dozen countries across South America and sub-Saharan Africa. About the same size as traditional passports and coloured like a dandelion, the document contains confirmation that the bearer has received a vaccine against a given disease – usually yellow fever, or polio.
Vaccine certificates, in one form or another, have been with us since the first days of air travel, when passengers were still vulnerable to many diseases now rare or eradicated, including typhus, cholera and smallpox. As our understanding improved on how these diseases spread, and how to fight them, the global mandate for vaccine passports waned. The Yellow Card is now most commonly associated with yellow fever: a tropical pestilence, once feared, now tamed by a vaccine that claims almost 100% effectiveness in preventing infection.
Quarantine is what’s killing our industry.
Alan Murray Hayden, IATA
Policymakers hope that a similar infrastructure will play its part in halting the spread of Covid-19 – and, in doing so, revive an international travel industry left moribund by a year of national lockdowns. “Quarantine is what’s killing our industry,” says Alan Murray Hayden, head of airport, passenger and security products at IATA.
By supplying digital proof of vaccination at the border, says Hayden, travellers would avoid the need to self-isolate for weeks after landing, restoring the appeal of air travel at a stroke. International carriers, too, would be able to end social distancing on flights and reduce the number of staff on duty at airports physically checking passengers’ paper certificates. “That’s the only way we’re going to open up travel,” says Hayden.
Questions remain, however, about the basic premise of vaccine passports – starting with the relevance of Yellow Cards as a precedent. “The parallels aren’t as parallel as we all think they are,” explains Harvard bioethicist and founder of Editing Nature, Natalie Kofler. Jabs against polio and yellow fever are so effective that a vaccine certificate essentially proves immunity. But there’s relatively little data on the long-term impact of the new Covid-19 vaccines, particularly when it comes to combating new variants and limiting transmission.
Even less is known about the risk that so-called vaccine ‘passports’ could entrench existing inequalities in international travel. “It’s a real balance between understanding the urgency of putting things in place now, but also understanding that we need to give this a lot of thought and consideration,” says Kofler. After all, such a system “could be in place for quite some time.”
So far, the use of Covid-19 vaccination certificates has largely been confined to domestic use cases, such as obtaining entry to bars and restaurants. The roll-out of these certificates has not always been smooth. Israel’s ‘Green Pass’, for example, has been roundly criticised as a ‘security disaster’ for its confusingly written code and vulnerability to hacking. The app also reveals information about the user, such as the date they received their jab, that is unnecessary to gain access to a nightclub but potentially useful for a fraudster.
These are the kinds of weaknesses the airline industry wants to avoid with its own vaccine certificate platforms, explains Hayden. “One of the key things we want to do is stop central databases of passenger data,” he says – not only to prevent it ever being compromised but also to avoid the unnecessary burden on airlines in securing it in the first place.
Crucially, any future travel pass needs to be interoperable. “It’s no use Country A producing a vaccine certificate which is communicated by a QR code if Country B is either unable or unwilling to check it, read it, and verify its validity,” explains Andrew Bud, chief executive of digital credentials company iProov. “To verify its validity, to read it, they need to understand it, which means that they need to have a common format.”
Fortunately, such a format may be right around the corner. “The general opinion of this industry is interoperability is going to be enormously facilitated by the work that the World Health Organisation is doing to develop a digital certificate of immunity and prophylaxis,” says Bud. Many expect this framework to be built around a form of secure identification known as ‘verifiable credentials,’ in which the user’s biometric data is secured using a cryptographic key and stored remotely using blockchain technology. This form of verification, says Bud, “has been in laboratories and in standards committees for a number of years now, but has never really been implemented on a large scale”.
Vaccine passports based on this technology are already being trialled in Estonia and the US. The IATA, meanwhile, has used it as the foundation of its new Travel Pass mobile app, which will debut later this year. The technology forestalls the need for airlines to collect and store data on travellers, says Hayden, meaning that the only people who need to consult the app are passengers and border guards. “It’s probably the first widespread use of blockchain technologies for the reasons for which they were originally invented,” he adds – a secure, verifiable ledger for storing vital records.
This is open to debate, with some arguing that the capacity for blockchain-based technologies to store health data at scale remains, at best, untested. International consensus on what information needs to be uploaded onto such apps is also likely to remain elusive.
“At the end of the day, it’s up to the governments to devise what data elements they want from passengers,” says Hayden. It will also be up to governments how they use it: China’s domestic vaccine passport appeared to broadcast the user’s location to local law enforcement agencies, according to an investigation by the New York Times.
To have and have not
Privacy isn’t the only concern surrounding digital vaccine passports. Their basic premise – that proof of vaccination confirms the bearer is unlikely to transmit Covid-19 – has not yet been definitively established. By contrast, the yellow fever vaccine is “fully established to be 99% effective at preventing transmission,” says Kofler. “It’s at a very different level than what we’re talking about with dozens of different approved vaccines around the world, with variable abilities to prevent transmission, and definitely able to prevent at least symptomatic Covid-19.”
Any digital vaccine passport would need to be updateable, in case a new variant reduces the effectiveness of an individual vaccine. To be truly safe, “these passports would have to have an expiry date on them”, explains Professor Melinda Mills, director of the Leverhulme Centre for Demographic Science. “You’d also have to be able to revoke them” in extreme cases.
It’s clear that vaccine passports are going to be benefiting more economically developed countries.
Natalie Kofler, Harvard University
The social impact of vaccine passports must also be reckoned with. “I think at this point it’s clear that vaccine passports are going to be benefiting more economically developed countries,” says Kofler, specifically those with a robust vaccination programme. Meanwhile, marginalised populations are likely to be excluded.
Refugees, for example – many of whom have remained at the periphery of mass testing programmes – are unlikely to receive any benefit, says Dr Sara Dehm of the University of Technology, Sydney. “In January 2021, the UNHCR estimated that only 57% of states have committed to including refugees in their national vaccine roll-outs,” says Dehm, who is co-authoring a study on the impact of the pandemic on both asylum seekers and refugees in Australia. As such, it may be years before many refugees are permitted to travel internationally.
Indeed, entire nations could be left out in the cold. The system can only work as intended if the vaccine certificates uploaded onto these apps are trustworthy. And while the authenticity of certificates from countries with robust e-health infrastructures such as the UK probably won’t be questioned, the same will not be true of countries with weak e-health sectors and high levels of corruption.
“If some bloke in a pharmacy in Ruritania gave me an injection, and then typed it into his computer, and somehow, mysteriously, a vaccine certificate was created, to what extent will the United Kingdom believe that a bloke at a computer did it because of a vaccination, or because you slipped him a fiver?” says Bud. “It starts to become an act of international trust.”
It is a leap of faith that more nations are willing to make. Austria, Greece, China and Spain have already begun exploring how to implement vaccine certificates for international travel, while the UK government has said it is considering doing the same (trials for a domestic version created by iProov and Mvine are ongoing.) Some Covid-19 travel passes may be ready for passengers by the summer season – although that may put undue pressure on developers. “The European Union has said they want their certificate out by June,” says Bud. “Well, that’s four months. That’s a tough call.”
The European Union has said they want their certificate out by June. Well, that’s four months. That’s a tough call.
Andrew Bud, iProov
Will vaccine passports become a permanent feature of international travel? For Covid-19, they are only needed until the disease mutates into a weaker seasonal virus like influenza – a process likely to take several years. And countries may keep them in place even after the pandemic has subsided, Bud believes. “Remember, the world has just gone through a terrible shock,” he says. “I think it’s going to be suffering from PTSD for some years. So, once instituted, I don’t think that vaccine certificates will be quick to go away.”
And vaccine passports may themselves mutate. If they prove the viability of the ‘verifiable credentials’ model, calls to replace paper passports will surely follow. “That model… has not been designed just to provide one vaccine certificate,” says Bud. “It’s been designed to provide the certificates for your whole life.”
iProov’s chief executive remains unconvinced that we’ll be using digital passports any time soon, however. Hayden disagrees. Much of the research that has gone into the IATA Travel Pass comes from a previous investigation into the feasibility of a truly digital passport, called ‘One ID‘. The ultimate goal, explains Hayden, was to combine distributed identity technology with facial verification cameras to see if the passport desk could be eliminated. “The legacy of the work we’ve done on the IATA Travel Pass is that, in the future, you’ll be able to just walk through airports,” says Hayden. “That will continue forever, hopefully.”
Before that comes the complicated business of reviving the travel industry – and with it, the livelihoods of millions. The decisions governments now face are unpalatable, at best. Even so, says Bud, “it’s our obligation as technology providers to provide society the infrastructure that will enable it to make the choices that need to be made. Without the infrastructure, society doesn’t have a choice”.