The head of the European Union's medical regulation agency says she does not believe the COVID-19 pandemic is over and that "we need to be prepared for what could be a difficult time" in the coming months-but added the agency will not rush through approval of vaccines targeting the Omicron variant.

In an interview in the Financial Times, Emer Cooke, head of the European Medicines Agency, or EMA, said that in contrast to how authorities in the United States were planning to roll out the new jabs as soon as possible, the EU would stick to its policy of making sure it could be completely confident in any vaccines it authorized.

Currently, there is no data to prove that new latest variant shots are any more effective than the one available for the initial form of the Omicron variant, known as BA.1.

"Irrespective of what is happening, we have to have confidence in the vaccines that we authorize, and that is our primary responsibility as we have done with all the vaccines that have been presented to us," she said.

"All this comparison between BA.1 and BA.4/BA.5 (variants) is something I think we're overfocusing on at the moment," she added.

"Promises are not enough for me … frankly, if we started a new wave tomorrow, I'd take the old vaccine, because that's what is available."

Previously, the chief executive of the BioNTech company, Ugur Sahin, had said it would be "useful" to adapt vaccines "without the requirement to do extra clinical trials" to try and get a grip before the virus mutated further, a view shared by the Moderna company.

But Cooke, who expects reviews of the Moderna and BioNTech shots to have been completed early next month, said the way different EU member states were being affected meant a more nuanced approach was needed, rather than rushing into things.

"Our priority is to ensure that the member states have a plurality of options available that would meet their individual strategies," she added.

In May, the EU ended its mask mandate for passengers on flights, and the increasing rollout of the vaccination program has led many people to drop their guard and take the novel coronavirus less seriously, but the mass movement of the summer holiday season in Europe has, unsurprisingly, resulted in more cases.

"It's now abundantly clear we're in a similar situation to last summer," the World Health Organization's Regional Director for Europe Hans Kluge tweeted last month.

Adam Macneil, an associate professor of immunology at Brock University in Canada, told Australian broadcasting network ABC it was apparent that vaccines alone were not enough in the "multi sub lineage Omicron era".

" (If) you're looking across Europe at the travel that's happening there, you would think everything was hunky dory ...but, you know, we can't get back to that normalcy without making these adaptations to our lives," he added.

The so-called vaccine-plus strategy he backs includes more public education about mask-wearing and policies to improve indoor ventilation, in addition to further vaccinations.