OTTAWA, Nov 19 (Reuters) - Canada on Friday authorized the use of Pfizer Inc"s (PFE.N) COVID-19 vaccine for children aged 5 to 11, paving the way for the inoculation of elementary school-age children across the country. Medical officials said the approval was timely, given that incidences of COVID-19 in Canada are now highest among those in the 5-to-11 bracket. The shot is the first to be made available for young children in Canada. Officials had made clear for weeks that the decision would be favorable. "After a thorough and independent scientific review of the evidence, the department has determined that the benefits of this vaccine for children between five and 11 years of age outweigh the risks," Health Canada said in a statement. Separately, Pfizer Canada said in it would begin sending shipments imminently. The vaccine will be given in two doses of 10 micrograms, three weeks apart. Adult doses contain 30 micrograms. "This authorization comes at a critical time in the pandemic," said Supriya Sharma, chief medical adviser to the federal health ministry. "Over the course of the third and the fourth wave, incident rates have been increasing among children less than 12 years of age," she told a briefing. Prime Minister Justin Trudeau said last month that Ottawa had signed a deal with Pfizer to quickly receive 2.9 million doses of the vaccine once it was approved. read more The U.S. Food and Drug Administration authorized use of the vaccine for those aged 5 to 11 on Oct. 29. read more Sharma said no known safety issues had emerged so far from the United States, where 2.5 million children have received their first doses. Health Canada said clinical trials showed the vaccine was 90.7% effective at preventing COVID-19 in those aged between 5 to 11 and no serious side effects were identified.