The Canadian Public Health Agency has declared that the flu season has officially begun. The Public Health Agency of Canada has reported an uptick in flu cases across the country, signifying the start of flu season. For the second week in a row, the percentage of flu-positive tests has stayed above 5%. As of Nov. 25, 7.5 percent of persons tested in Canada have the flu. Dr. Allison McGeer, an infectious disease specialist, explains. The H1N1 strain of influenza A is currently circulating. McGeer emphasized the importance of flu vaccinations.