A 12-year-old in Hennepin County and a 25-year-old woman in Olmsted County are Minnesota's first confirmed cases of seasonal influenza for the 2012-13 flu season, the Minnesota Department of Health said Friday.

While occasional flu cases occurred over the summer, the state didn't start its full-scale seasonal influenza surveillance until Oct. 1. Both cases were confirmed this month. Neither person required hospital care.

The Health Department said these first cases are a good reminder for Minnesotans to get seasonal vaccines against influenza, a viral infection that typically causes sore throats, fevers, headaches, muscle aches and extreme fatigue.

From 3,000 up to 49,000 Americans die each year from seasonal influenza, with the elderly, young children and people with chronic diseases being at greatest risk.

The first two cases involved a B strain and an H3 strain of the virus -- both unrelated to the swine flu that rippled through Minnesota over the summer. The tests used to confirm the cases did not include lab cultures of the viruses, so the state is unable to say whether they are closely matched to the strains included in this year's influenza vaccine, said Kris Ehresmann, the state Health Department's director of infectious disease epidemiology.