The idea of vaccine certificates has gained traction in England, as the government weighs their potential usefulness in reopening sectors of society against concerns about privacy and discrimination.
As ministers prepare to launch a review into whether to introduce the documents, here are the key questions to be answered.
What might they look like?
It is still very early days, with the prime minister, Boris Johnson, only announcing on Monday that the certificates are being considered, after months of denials by senior cabinet figures.
But if they were adopted, the documents could be displayed using an existing application people may have on their smartphones, likely one run by the NHS. The government has denied the contact tracing app will be used.
Dr Pete Calveley, CEO of the care home provider Barchester Healthcare, has said he will expect the myGP app to be used by staff to prove they have had a coronavirus vaccine.
What is the precedent?
While the idea of vaccine passports for international travel has been talked about, the use of certificates in domestic settings like theatres and restaurants is a new development.
Johnson said on Tuesday that “this is an area where we’re looking at a novelty for our country. We haven’t had stuff like this before.
“We’ve never thought in terms of having something that you have to show to go to a pub or a theatre, so there are deep and complex issues that we need to explore. Ethical issues about what the role is for government in mandating people to have such things, or indeed banning people from doing such a thing. There are complex issues we need to work out.”
Where in the world are they already used?
Israel, where Covid vaccines are being rolled out fastest, has already introduced a “green pass” for those either already inoculated or who have presumed immunity after contracting Covid.
The pass grants access to gyms, hotels, swimming pools, concerts, and places of worship. Restaurants and bars will be included from early March.
For everyone without a pass, including children under 16 who are not eligible for the jabs yet, many of the activities shut down during the year-long crisis will remain off-limits, although some will be available if they provide a negative coronavirus test.
Other countries are also much further along than the UK in developing immunity passports for international travel. Greece has already signed a deal with Israel to accept green passes, and is pressing the case for EU countries to adopt a bloc-wide approach.
The World Health Organization’s director general, Tedros Adhanom Ghebreyesus, has counselled caution over vaccine passports, saying last month: “We cannot afford to prioritise or punish certain groups or countries.”
Who is for and against them?
Johnson has acknowledged that Conservative MPs might be opposed to the certificates on ideological grounds.
“I know fervent libertarians will object, but other people will think there’s a case for it,” he said on Tuesday, after criticism from thinktanks Liberty and Big Brother Watch.
Unions may back the certificates as a measure to protect workers and ensure the conditions they are working in are as safe as possible. But they will also be mindful of employers potentially locking out some staff who are not able to get a jab.
Tony Blair, the former prime minister whose suggestions have helped influence government thinking on coronavirus, has backed the idea.
• This article was amended on 24 February 2021. Due to incorrect information that was supplied, an earlier version indicated that the NHS contact tracing app could be used for Covid certificates. This is not the case, and has been clarified in the article.
