News report predicted that this winter's flu

This winter’s flu season is turning into a "moderately severe" one that might get worse because of an imperfect vaccine and steady cold weather, flu experts and public health officials said this week.

The flu is now widespread across the country and the peak of transmission probably occurred during the Christmas-New Year’s holiday week, just as many people were crowded into planes, buses and cars or in large family gatherings, said Dr. Daniel B. Jernigan, director of the influenza division of the Centers for Disease Control and Prevention.

About 80 percent of cases are of the H3N2 strain, which caused many hospitalizations and deaths this year in Australia, where winter comes in July and August.