The European Union's drug regulator is prepared for the possibility that Covid-19 vaccines may be tweaked to fight the new Omicron variant, although there is no evidence yet that it will be necessary, the agency's chief has said.

“There is no answer whether we will need to adapt vaccines,” European Medicines Agency Executive Director Emer Cook said in a media briefing, reports Reuters.

She said the European Union has the capacity to make 300 million doses of vaccines per month as drugmakers have ramped up output to meet the growing demand for the bloc's 450m population.