But it can kill even the young and otherwise healthy. On average, the CDC says flu kills about 24,000 Americans each year, and last year, the toll included 105 children.
Last year, three-fourths of babies and toddlers — tots ages 6 months to 2 years — were vaccinated. So were two-thirds of adults 65 and older.
HOW WELL DOES THE VACCINE PROTECT?
The CDC says people who get flu shots have a 40 percent to 60 percent lower chance of getting seriously ill than the unvaccinated. If someone is infected despite vaccination, generally they have a milder illness than if they'd skipped the shot, said Dr. William Schaffner of Vanderbilt University and the National Foundation for Infectious Diseases.
"I like to tell my patients, 'You're here complaining, that's wonderful — you didn't die,'" he said.
The regular flu shot comes in versions that protect against either three or four strains of influenza — including that problematic H3N2 strain, another Type A strain known as H1N1, and one or two strains of Type B flu.
Ask your doctor or pharmacist about other options which are available for certain age groups.
For needle-phobes, there's a skin-deep vaccine that uses tiny needles, and a needle-free jet injector that shoots another vaccine through the skin.
Two vaccine brands target the 65-and-older crowd. They're especially vulnerable to flu's dangerous complications because they tend to have more underlying health problems than younger people — and because standard flu shots don't work as well with age-weakened immune systems. One high-dose version contains four times the usual anti-flu ingredient, while a competitor contains an extra immune-boosting compound.
And for those worried about allergies from eggs used in the production process, two more vaccines are egg-free.
SORRY KIDS, NO NASAL SPRAY OPTION
FluMist, a less ouchy nasal spray vaccine, once was popular with children. But last year, a baffled CDC said it was no longer protecting against certain influenza strains as well as regular flu shots — and told doctors not to use it. That's the same advice this year: Youngsters will need a shot, just like their parents.
And for kids between the ages of 6 months and 8 years who are getting a first-ever flu vaccination, they'll need two doses a month apart.