In the week that the UK became the first country to approve the Pfizer/BioNTech coronavirus vaccine, there is, at last, a glimmer of hope that life around the world might to return to something like normal.
There is also growing interest in how people can prove they have been vaccinated.
On the Tech Tent podcast this week, we look at the practical and ethical issues around digital vaccination records.
Back in the spring, my inbox started filling up with companies pushing health, or immunity, passports.
Everybody - from facial recognition businesses to digital identity experts - was touting technology which could verify whether the user had recently had a negative coronavirus test.
This, they argued, would be a vital tool for any business wanting to check that employees or visitors to its premises were not putting others at risk.
But without government backing - and with knowledge about the nature of Covid-19 and the accuracy of tests still hazy at that stage - none of these schemes went very far.
Now things have changed.
Quite soon, millions of people will have been vaccinated, and they may want a simple way to show they no longer pose a threat of infection.
Some businesses may even demand it.
The Australian airline Qantas has suggested it may need to see an "immunity passport" before passengers are allowed on board.
The UK government has suggested it may look at making vaccination records a feature of the NHS Covid-19 contact-tracing app in England and Wales.
On the podcast, we hear from an immunologist and a lawyer who both foresee challenges for governments pushing ahead with vaccination passports.
Professor Deborah Dunn-Walters, chair of the British Society for Immunology, says, from a personal point of view, she sees some benefits.
"I'd like an app on my phone that has all the vaccines I've ever had - and pops up and tells me when they expire."
But she worries about the implications of only letting people into places such as pubs or restaurants on the condition that they have such an app.
"I think it gets into a complicated ethical argument if you're saying to people, you can't live your day-to-day life unless you get this."
Dr Ana Beduschi, an associate professor of law at the University of Exeter, agrees. She has been researching immunity passports and says they present legal problems.
"If the restaurant owner wants me to show my vaccination records or Covid test results - even if I consent, as an individual, to have my health data collected, stored, and processed - providers would still need to build data protection into the design of these technologies by default."
In addition, Prof Dunn-Walters says it's too early to talk about vaccination passports when there are still things we don't know about the vaccine.
"We have evidence that having a vaccine would protect me, but not necessarily that it would protect my family or anybody else I come into contact with," she explains.
From the start of the pandemic, there have been arguments about balancing the rights of the individual against wider society.
There have also been questions about whether we should worry less about our data privacy, and more about the freedom to leave our houses and mingle with others.
But Dr Beduschi argues that freedom of association, as well as privacy, would be imperilled if the authorities decided only people with immunity passports could use public transport or attend churches, for example.
She warns that the coronavirus pandemic has already had a disproportionate impact on some groups.
"Deploying digital health passports could further deepen the existing inequalities in society," she warns,
China has already sought to use smartphone apps during the pandemic to display its citizens' virus status and control their movements.
But in many countries there has been a growing backlash against that idea.
Governments keen to get the public to trust Covid vaccines may need to be cautious about following China's example.