Europe is warming to the idea of so-called vaccine passports—but with a possible third wave of COVID-19 infections looming in some countries, it’s not quite there yet.

At a Thursday meeting, the European Union’s national leaders (a group called the European Council) discussed the common vaccination certificates that could help to restart European travel. Council President Charles Michel said after the meeting that the leaders “agreed to continue our work on a common approach.”

“More work needs to be done—on digitization and on cooperation with the World Health Organization,” Michel said. “But tonight we felt more and more convergence among us on this important topic. The European Council will revert to this matter.”

Crucially, the leaders agreed to keep restricting nonessential travel for the time being. “We are determined to continue to work together and coordinate our action to tackle the pandemic and its consequences. The epidemiological situation remains serious, and the new variants pose additional challenges. We must therefore uphold tight restrictions while stepping up efforts to accelerate the provision of vaccines,” the council said.

German Chancellor Angela Merkel suggested after the meeting that common digital vaccination certificates could become a reality by the summer.

Southern push

The primary push for European vaccine passports is coming from Southern Europe—countries like Greece, Spain, Italy, and Portugal, which are heavily reliant on tourism.

Greece started issuing digital vaccination certificates this week to those who have received both doses of the COVID-19 vaccine. These are initially for medical use within Greece, but Digital Governance Minister Kyriakos Pierrakakis suggested wider European adoption could create “a kind of fast lane inside the airports.”

“Especially as far as border crossings are concerned, we are very optimistic that this proposition will be adopted, because if it doesn’t, we will face the absurd version, where someone that is vaccinated still needs to get tested or quarantined—when these resources can be used better for other citizens,” Pierrakakis said.

Earlier this month, Greece struck a deal with Israel that will allow vaccinated people to travel between the two countries without quarantine. So did Cyprus, and Israel is also in talks with Malta. At the moment, Israel isn’t permitting any foreign nationals to fly into the country from abroad unless it’s to attend a funeral.

Israel has already managed to at least partially vaccinate half its population—an achievement that remains a far-off aspiration for EU countries.

Tiny Malta has managed to give nearly 11% of its people at least one jab, and that’s the highest rate in the EU by some measure. Denmark is in second place with 7.4% of its people at least partially vaccinated, and the southern EU countries are all hovering around the 4% to 5% range (as are Germany and France).

Add to that the fact that the spread of more infectious coronavirus variants is causing case numbers to rise again in countries such as Germany, France, and Greece, and it is not hard to see why the EU as a whole is playing it cautious for now. After all, while there have been promising signs that some already authorized COVID-19 vaccines might cut infectiousness, this is not yet a sure thing.

According to Bloomberg, French President Emmanuel Macron expressed worries during the council meeting about how long vaccine-derived immunity might last and how infectious vaccinated people might still be. (The report also noted that European Commission President Ursula von der Leyen told the gathering Google and Apple were preparing to step in to create vaccine certificates with the World Health Organization if the EU did not take the initiative, but the WHO has flatly denied having talks with the tech firms.)

Discrimination and privacy

There are also fears that vaccine passports could end up being discriminatory against those who have not yet been able to get the jab.

The Israeli digital vaccination certificate (known as the Green Pass) gives people the ability to visit restaurants and entertainment venues—old-school joys that are not available to the unvaccinated.

This makes the pass something of a carrot in the quest to ensure enough citizens agree to being vaccinated, and the Israeli health ministry is not being shy about that fact. “With the Green Pass, doors just open for you,” it says in a campaign that launched last week. “How to get the pass? Go and get vaccinated right now.”

Germany, for one, is being extra cautious on this front. Its national Ethics Council said earlier this month that vaccinated people should not get additional freedoms until there is greater clarity about vaccines and infectiousness. Interior Minister Horst Seehofer has also warned that such discrimination could effectively amount to making vaccination mandatory, which it is not.

The future use of common certificates “does not mean that only those who have a vaccination passport are allowed to travel,” stressed Merkel after Thursday’s council meeting.

Some human rights activists also see vaccine passports as a potential privacy threat.

“You are asked to provide data about the state of your body as a condition to entry,” the Dutch digital-rights organization Bits of Freedom warned in December. “This is highly intimate and sensitive data. Even in the middle of a health crisis we should carefully judge whether sharing health data outside the medical realm is really necessary.”