Health passports: few topics in the COVID-19 era stoke more debate.
Many leaders see them as a key to normality but others just see a door to discrimination.
[London resident David Ross, saying:] “... scrap it and let's just get on with life again. Stop trying to control the people."
The best case study to see the tensions at play is the European Union, which has proposed the ‘Digital Green Certificate' to help revive a tourism industry on its knees after southern states warn their economies can’t withstand another summer of deserted beaches.
But developers are facing a host of issues, ranging from the practical to the philosophical and moral.
The EU-wide pass is slated to launch in June and will allow travelers to cross borders freely again if they have been vaccinated, tested negative, or recovered from COVID-19.
The pass would be issued by a doctor or health center and feature a QR code that can be scanned into a smartphone app, giving people a portable proof of immunity in their pocket.
There isn’t going to be one pan-European app; the 27 member states are each creating their own.
Estonia is considered to be the furthest along but others aren't far behind.
France is already testing its app for airline flights.
Alongside Germany, it’s planning to add to or build upon its pre-existing contact-tracing app.
The European Commission plans to issue a contract for a central gateway, making it possible for all the separate national apps to 'talk' to each other.
That would assure that, say, the German app could easily be read in Portugal.
If you think it all sounds pretty complicated, that’s because it is - and there are many issues being wrestled with.
For one, there is a big question mark over whether vaccines or past infection really do lead to immunity.
The WHO has spoken out numerous times against the scheme for this very reason.
[WHO Spokeswoman Margaret Harris, saying:] “...we, as WHO, are saying at this stage, we would not like to see vaccination or the vaccination passport as a requirement for entry or exit because we are not certain that - at this stage - that the vaccine prevents transmission and there are all those other questions, apart from the question of discrimination against the people who are not able to have the vaccine for one reason or another."
That second point mentioned - discrimination - is another big concern being voiced on streets across Europe.
[Azuzona Gonzalez, saying:] "There are many of us who don't want to get vaccinated because we don't trust these vaccines. If they were vaccines like those for tetanus or chicken pox, then yes, but I don't trust such a new vaccine. But I don't have to be locked in my house and be discriminated like other people who haven't been vaccinated."
The EU has already promised to open its doors to vaccinated Americans this summer.
However no global standard has yet been agreed, meaning work still needs to be done to deal with overseas visitors in Europe.
Member states also worry about the security of personal information and if the scheme would be vulnerable to fraud.
Concerns about digital tracking, too, loom large.
The European Commission has promised the health passes will contain minimal data.
Anything sensitive will typically be stored locally on smartphones, while the EU gateway will only handle the signatures on digital certificates.