The European Union has agreed to fast-track approvals of vaccines updated to target coronavirus variants, the bloc's health commissioner said Sunday, following criticism of the EU's sluggish vaccine drive.

"We looked at the process together with the European Medicines Agency (EMA)," Stella Kyriakides told German daily Augsburger Allgemeine in an interview.

"And we have now decided that a vaccine, which has been improved by a manufacturer based on its previous vaccine to combat new mutations, no longer has to go through the entire approvals process.

"So it will be faster to have suitable vaccines available without cutting corners on safety," she said.

The EU's vaccine rollout has been snagged by delays and controversies, leaving it lagging behind countries like the United States, Britain and Israel where a larger share of the population has been injected so far.

European Commission chief Ursula von der Leyen last week admitted that mistakes had been made in procuring vaccines on behalf of all 27 member states.

She told the European Parliament that the bloc had been late to authorise jabs, and had underestimated the difficulties of vaccine mass production.

She also warned that scientists do not yet know if the vaccines approved so far -- those by BioNTech/Pfizer, Moderna and AstraZeneca/Oxford -- will remain effective against new mutations.

"But we do know these variants will continue to emerge. And we do know that we need to anticipate and prepare immediately," she said.