Flu activity in Tennessee is picking up faster than a sneeze, particularly among young and middle-age adults. The U.S. Centers for Disease Control and Prevention has found the predominant strain this year is H1N1, the same strain responsible for the 2009 pandemic.According to family nurse practitioner Theresa Hill of Family Care Clinic at Northgate Center, the time to think about being vaccinated is now.“About 20 percent of the people I have seen today have had the flu,” Hill said Tuesday. “One lady I saw the other day came back and she’s probably got pneumonia.