BRUSSELS (AP) — European Union leaders sought to inject new energy and a fresh sense of unity into the bloc’s lagging coronavirus vaccination efforts Thursday as concern mounts that new variants might spread faster than authorities can adapt.

The leaders opened talks via videoconference and debated ways to ease production bottlenecks and speed up the rollout of vaccines, as well as the severity of restrictions that should remain in place to halt the spread of the virus, which has killed more than 531,000 people across the bloc's 27 nations.

Divisions among EU member countries, including Germany, Austria and the Czech Republic, on tight border restrictions to stave off transmission has again raised the specter of travel delays and long traffic backups in a bloc that prides itself on being a seamless market.

“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 leaders will say, according to a draft summit statement seen by The Associated Press.

The European Commission has sealed deals with several companies for well over 2 billion vaccine shots — far more than the EU population of around 450 million — but only three have been authorized: jabs from Pfizer-BioNTech, Moderna and AstraZeneca. Officials say the Johnson & Johnson vaccine could be approved next month.

Not far from where European Council President Charles Michel chaired the video summit from Brussels, EU lawmakers grilled the heads of the big pharmaceutical companies.

AstraZeneca CEO Pascal Soriot fielded many questions from the European Parliament, especially after he confirmed that the company would deliver less than half the vaccines it had committed to in the first quarter. The EU has partly blamed supply delays for lagging far behind nations like Israel, the United States and Britain when it comes to vaccinations. By early this week, 6.5% of the adults living in the EU had been vaccinated, compared to more than 27% in the U.K.

Soriot said AstraZeneca would deliver 40 million doses to the EU in the first quarter, attributing the delay to complicated production issues, including “lower than expected output in our dedicated European supply chain."

Moderna CEO Stephane Bancel said production problems are inevitable as companies work around the clock to do in one year what normally takes 3-4 years. Most of the company chiefs said they expect an improvement in the second quarter.

“Every time there is a human error, equipment breaking down...or raw material from one of our suppliers late by a day, you cannot start making the product because it will not be safe, you will not have the right quality,” Bancel said, explaining the technological issues facing producers.

Soriot said a big challenge is to improve yield - the number of doses that can be extracted from a liter of vaccine. He also rejected the idea that companies can simply open new production sites to solve the problem, saying that engineers must spend a lot of time training staff.

“Our teams are absolutely stretched to the maximum. There’s no way they could train any more people,” he said. Soriot insisted that most companies developing vaccines probably face the same constraint.

During their summit, the EU leaders also weighed whether and when to introduce vaccine certificates, which could help smooth a return to air travel and possibly avoid another disastrous summer holiday season, as the tourism industry and broader economies suffer from restrictions.

Southern European countries dependent on tourism, like Greece and Spain, support such a system, but their northern EU partners, like Germany, doubt whether the certificates would work.

“First it must actually be clearly resolved that vaccinated people are no longer infectious,” German Chancellor Angela Merkel said in an interview published Thursday in the daily Frankfurter Allgemeine Zeitung. “As long as the number of those who have been vaccinated is still so much smaller than the number who are waiting for vaccination, the state should not treat the two groups differently.”

Austrian Chancellor Sebastian Kurz said he would prefer a green pass system, similar to Israel’s.

“Those who are vaccinated should have full freedom, but so should those who just had corona and are immune, and all those who take a test and can prove through the test that they are negative,” Kurz told Germany’s Bild tabloid.

Public pressure to relax measures is building. The Netherlands has eased some lockdown measures in what Prime Minister Mark Rutte called a calculated risk to make the year-long crisis “bearable.” Denmark just allowed high school students to partially return to classes.

In Belgium, Jean-Marc Nollet, head of the Greens party that is part of the ruling coalition, openly said he no longer followed his own government’s limits on social contacts because “I am a human being and human contact is something vital.”

But according to the draft statement, the leaders will say that the crisis is far from over, especially as vaccine production lags, and that restrictions on nonessential travel, among other measures, remain valid.

With leaders conscious that the pandemic won't end unless it’s defeated everywhere, summit talks will also touch on getting vaccines to other countries in need, notably in Africa, through the U.N.-backed COVAX program.

Geir Moulson in Berlin contributed to this report.

Copyright 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission., source Associated Press News