Health officials say this flu season is shaping up to be one of the more severe in recent years.
Earlier reports indicated that this could be a bad flu season, and the Centers for Disease Control and Prevention says the data now confirm it. In the last week of December flu was widespread in 41 states; flu-related child and infant deaths climbed to 18 and outpatient visits for flu symptoms had jumped to 5.6 percent.
The CDC's Tom Skinner says "people who come down with the flu can be pretty sick," with severe muscle aches and high-grade fever lasting 4 or 5 days.
Skinner says for "certain groups of people -- mainly children, the elderly, people with underlying health conditions -- it can be life-threatening."
He says the vaccine is well-matched to this year's flu strains, but isn't 100 percent effective. It does reduce the severity of the illness for those who do get it, though -- so it's still worth a shot.