Flu Vaccine Not as Effective This Year

Posted on February 15, 2008

Deciding what strains of flu go into the flu vaccine each year is a guessing game played by scientists. Most years, they guess right. But this year they did not. This year's flu vaccine protects against only 40% of the flu strains that are circulating out there.

The flu shot is a good match for only about 40 percent of this year's flu viruses, officials at the U.S. Centers for Disease Control and Prevention said Friday. That's worse than last week's report when the CDC said the vaccine was protective against roughly half the circulating strains. In good years, the vaccine can fend off 70 to 90 percent.


Each winter, experts try to predict which strains of flu will circulate so they can develop an appropriate vaccine for the following season. They choose three strains -- two from the Type A family of influenza, and one from Type B. Usually, the guesswork is pretty good: The vaccines have been a good match in 16 of the last 19 flu seasons, experts said.

But the vaccine's Type B component turned out not to be a good match for the B virus that has been most common this winter. And one of the Type A components turned out to be poorly suited for the Type A H3N2/Brisbane-like strain that now accounts for the largest portion of lab-confirmed cases.

Bottom line: there is lots of flu out there, so use antibacterial gel and stay away from sick people. And for Pete's sake, if you have the flu stay home from work so you don't infect everyone there.

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