Jan 10 (Reuters) - The European Union"s drug regulator said on Monday it could issue "within weeks" a decision on whether to approve the use of Pfizer"s COVID-19 pill, Paxlovid, after the U.S. drugmaker submitted an application seeking authorisation. The approval sought is for the treatment of mild-to-moderate COVID-19 in patients 12 years of age and older, weighing at least 40 kilograms and are at high risk of their illness worsening, the European Medicines Agency said. While vaccines are central to the fight against the pandemic, regulators are looking at therapies as a new tool against the fast-spreading Omicron variant, which has now been detected in more than 128 countries around the world. The EMA has already evaluated a portion of the data during a rolling review of Pfizer"s pill that began in November. Pfizer"s two-drug regimen called Paxlovid, which is meant to be taken at home for five days soon after onset of COVID-19 symptoms, was authorized for people aged 12 and older by the U.S. Food & Drug Administration in December. In a clinical trial, it was nearly 90% effective in preventing hospitalizations and deaths in patients at high risk of severe illness.