3 things you should know about this year's deadly flu

This year's flu vaccine is only about 60 percent effective overall, according to the latest research by the Centers for Disease Control and Prevention. If you haven't been vaccinated yet, don't let the effectiveness rate dissuade you. The flu virus is still circulating widely (see map above), and it's predominantly H1N1, the same potentially deadly bug that caused a worldwide pandemic in 2009.

"Influenza can make anyone very sick very fast, and it can kill," said Tom Frieden, M.D., director of the CDC. "Vaccination every season is the single most important thing you can do to protect yourself."

The CDC recommends that everyone 6 months and older get an annual flu vaccine, including pregnant women and others who are at higher risk of serious complications. It's not too late. Flu season is likely to continue for several more weeks, especially in the West and Northeast, where infections are still widespread, according to the current issue of Morbidity and Mortality Weekly Report. Among the report's three key findings:

• This flu season is hitting middle-aged and younger adults hardest. As of early February, 352 people ages 25 to 64 have died of influenza, accounting for 62 percent of all flu deaths. Mainly, that's because when the flu season began, only a third of people in that age group had been vaccinated, including those at high risk because of underlying health conditions such as diabetes, obesity, and asthma.
• Whether you've been vaccinated or not, if you think you're coming down with the flu, seek medical care promptly. If you have signs of infection, especially if you have underlying conditions, getting prescription antiviral medications early could make a big difference in how likely you are to develop even more severe illness.
• This year's flu vaccine is working, but not as well as public health officials wish it would. Vaccine effectiveness ranges from 67 percent for children 6 months to 17 years old and 60 percent for ages 18 to 64 to only 52 percent for people 65 and older. (Seniors' immune systems respond less strongly to the vaccine.)

Public-health officials hope next season's flu vaccine will work better. A Food and Drug Administration advisory committee will decide this week which flu strains to include in it.  CDC officials said they highly recommend people get vaccinated against influenza every single year, even if the formulation remains the same. Like any vaccine, the duration of protection can wear off, just as the shots you got as a child for diseases such as tetanus and diphtheria don't last a lifetime.

—Doug Podolsky

Read more about which vaccines you should get and when in order to boost your immunity. And use the new HealthMap Vaccine Finder to locate vaccine providers near you.