This year's recommended flu vaccines include:

• A trivalent dose, protective against three influenza strains, for people 3 and older; there’s a high-dose version for those 65 and up

• A quadrivalent dose that protects against four strains (different versions are for anyone 6 months or older)

• A recombinant vaccine for folks 18 and up.

All influenza vaccines are 63 to 65 percent effective at preventing the flu. You're not totally protected, but if you do get the flu, you'll have a milder case.

Each year, about 235,000 people are hospitalized (20,000 are kids) because of the flu. And though yearly death rates vary, recently they've been as high as 49,000.

The groups most at-risk from the flu are older adults, young children, pregnant women (the vaccine also protects the yet-to-be-born for the first six months of life), and anyone with a compromised immune system.