The European Union must consider mandatory vaccination to tackle the spread of the “highly contagious” omicron variant, Ursula von der Leyen, the European Commission’s president, has said.

In a rallying cry, she urged the EU’s 27 member states to step up their vaccination campaigns, roll out booster doses and consider new travel restrictions in response to the emergence of the mutant strain in Europe.

Mrs von der Leyen, a former medical doctor, said mandatory immunisations must be considered as a policy to counter the worryingly low take-up across the bloc, which has some 150 million people not vaccinated against the disease.

Asked whether she supported mandatory jabs, she told reporters on Wednesday: “We have the vaccines, the life-saving vaccines, but they are not being used adequately everywhere. And this costs … This is an enormous health cost coming along.

“If you look at the numbers, we have now 77 per cent of the adults in the European Union vaccinated or if you take the whole population, it’s 66 per cent. And this means one-third of the European population is not vaccinated. These are 150 million people.

“This is a lot, and not each and every one can be vaccinated – children, for example, or people with special medical conditions – but the vast majority could and therefore, I think it is understandable and appropriate to lead this discussion now.

“How we can encourage and potentially think about mandatory vaccination within the European Union, this needs discussion. This needs a common approach, but it is a discussion that I think has to be met.”

But Mrs von der Leyen conceded the question was out of her hands because such a decision is a “pure member state competence”, adding: “It is not for me to make such a recommendation.”

Greece and Austria have moved to introduce mandatory vaccinations, with fines for anyone who doesn’t comply with their diktats.