North Dakota health officials are encouraging residents to pay attention to potential flu symptoms after five influenza-associated deaths this flu season — with two deaths in children younger than 10.

During the 2014-15 flu season, the poor match between the virus used to make the world's vaccine stocks and the circulating seasonal virus yielded a vaccine that was less than 20 percent effective.

Add Yahoo as a preferred source to see more of our stories on Google. North Dakota health officials are urging residents to be cautious amid a surge in flu activity, with five flu-related deaths ...