Flu season in the U.S. is off to its earliest start in nearly a decade —  and it could be a bad one according to the CDC.

Health officials on Monday said suspected flu cases have jumped in five southern states, and the primary strain circulating tends to make people sicker and It is particularly hard on the elderly.

The good news is that more than a third of Americans have been vaccinated, and the vaccine is well-matched to the strains of the virus seen so far, CDC officials said.

Higher-than-normal reports of flu have come in from Alabama, Louisiana, Mississippi, Tennessee and Texas. Flu-related hospitalizations are also rising earlier than usual, and there have already been two deaths in children.