NOW that things are opening up again in Scotland, there is a lot of speculation about how we can ‘get back to normal’ as safely as possible. The approach so far has been to focus on our behaviour and the places where people interact. Requiring face coverings and distancing, improving ventilation, putting up signage and screens.

But an alternative approach is to specify which groups can do certain things. Given we now know that Covid-19 vaccines protect against the disease and there is growing evidence that they also reduce transmission, it’s not a big leap to suggest that people who have been vaccinated are at less risk, and pose less risk to others. This is where requiring proof of vaccination comes in.

Israel and Denmark already have certification schemes to allow access to shared indoor public venues such as restaurants and cinemas on the basis of having received both doses of a Covid-19 vaccine, proof of an earlier infection or a recent negative test result. Estonia has also developed a digital vaccine certification programme, VaccineGuard, through its national patient portal.

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In the UK, people are broadly supportive of vaccine passports. In an Ipsos MORI poll conducted at the end of March, over half of those surveyed were in favour of them for a whole variety of activities. Strongest support (over 70%) was for international travel and being able to visit a relative in a care home or hospital. There was even support from half of those polled to require them on public transport (58%) or to go to the hairdresser (56%).

But vaccine certification is fraught with difficulties and is controversial. The Scottish Government has been clear that they have no plans to introduce a domestic scheme anytime soon. We are all still coming to terms with the latest app Checkin Scotland that helps us provide details to NHS Test and Protect when we visit a cafe, pub or other hospitality venue.

Uptake of the Protect Scotland app (designed to tell if we’ve been in close proximity to someone who tests positive) has been more limited than hoped, with just over 1.8 million downloads as of February 2021 in a population of over-16s of 4.5 million. Younger children aged 12 and above were eligible to download the app from mid December 2020 but it is unclear how many have done so.

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What are the main concerns about a vaccine passport scheme? First, we can look at what studies tell us. Last month my colleague Professor John Drury co-authored a rapid review of studies on attitudes and behaviours to Covid-19 health certification (proof of vaccination, a negative test or antibodies from a prior infection). He and colleagues involved in the review found 33 studies from a variety of countries, including ten from the UK. Certification of vaccination or antibodies was generally supported for international travel and protecting more vulnerable groups (ie hospital and care home visiting). Public attitudes were more negative in terms of requiring certification for access to education, workplace or religious settings.

There was some evidence from the studies that those with certificates might change their behaviour, being less likely to observe social distancing or engage in handwashing. The review also found that requiring people to be vaccinated before providing access to various activities wouldn’t necessarily increase vaccine uptake.

Other questions about vaccine passports are practical. At the moment in Scotland we don’t routinely receive a card confirming we’ve received our first or second dose even though this is recorded in our NHS records. In England, the NHS app (used by some to order repeat prescriptions and book GP appointments) may soon include a feature to show whether someone has been vaccinated or had a recent Covid-19 test. We don’t yet know how this will be done in Scotland, or indeed what the alternative would be for people without smart phones.

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There are also ethical considerations, particularly for vaccine status. These focus on inequalities – the fact that younger people are not yet eligible for vaccines and that uptake has been lower in more deprived areas and among some ethnic communities. Requiring proof of vaccination could exclude these groups from key aspects of social and economic life.

It’s pretty clear, however, that some form of certification is on the cards for international travel. There is already a precedent for this with yellow fever, where proof of vaccination is required for entry to a number of countries in Africa and the Americas. All three of the main European Union institutions (the Commission, Council and Parliament) have indicated support for an EU Covid-19 certificate. This will allow people to travel more freely between EU member states for those who have been vaccinated or have evidence of a recent infection or negative test. Discussions are underway with the World Health Organisation to identify if the certificate can be used for travel outside of Europe. It seems likely that the UK will develop something similar as part of proposals to restart non-essential international travel.

We will hear much more about this in the coming weeks. Let’s hope a system can be developed that is secure, easy to access and takes into account the needs of different groups and communities. This could be an important step in terms of more freedom of movement internationally. But vaccine passports for activities other than travel is something we should approach with real caution.

Linda Bauld is Chair of Public Health at the University of Edinburgh