Dec 21 (Reuters) - The European Union"s drug regulator said early data shows a booster dose of a COVID-19 vaccine helps restore some protection against the new Omicron variant, although there is no evidence yet that tweaks to existing shots will be necessary. "Data is showing that indeed there is a drop in the ability of the (COVID-19) vaccine to exert good neutralisation for Omicron," said Marco Cavaleri, head of biological health threats and vaccines strategy at the European Medicines Agency (EMA). "A booster dose is indeed able to restore quite (a) high level of protection from symptomatic disease," he said later in the same briefing. Doctor Stephanie Kossow vaccinates a man during a vaccination event against the coronavirus disease (COVID-19) at the Samariter Church in Berlin, Germany, December 20, 2021. REUTERS/Hannibal Hanschke EMA Executive Director Emer Cook said the watchdog is prepared for the possibility that COVID-19 vaccines may be tweaked to fight the variant. "There is no answer whether we will need to adapt vaccines," she said in the briefing. Cook said EMA needs more data on vaccine efficacy, the variant"s transmissibility and the severity of disease it causes. She said that when EMA gave the regulatory greenlight a year ago for the vaccine developed by Pfizer (PFE.N)-BioNTech (22UAy.DE), the first in the region, she did not think there would still be a pandemic now. The European Union has the capacity to make 300 million doses of vaccines per month as drugmakers have ramped up output to meet growing demand for its 450 million population, she said.