If you're one of the many Americans who dutifully got a flu shot last year only to find yourself down for the count with the dreaded respiratory virus anyway, health officials want you to know that they are doing all they can to make this winter better.

The 2014 formulation, by all accounts, was a disaster thanks to a surprise strain -- a mutated form of H3N2 -- that caught everyone off guard. Things were so bad that last year, 145 children died from the flu. In an average year it's closer to 100.

Flu shots typically contain a mix of three to four different strains of flu that health officials and industry predict may be circulating that season, based on a complex analysis that includes reports from hospitals, sampling of viruses and modeling programs. The vaccines take months to produce, and it can be tricky to guess what might happen that far in advance. Sometimes they're on the mark and the flu season is mild. But when they're not, it can be dangerous and hospitals can fill up with people suffering from serious and sometimes deadly flu.

Last year's shots were only 13 percent effective against H3N2 because of what scientists call "drift" or antigenic change in the virus that involves a change in its surface proteins that evades a host's immune response. Flu shots are typically 50 to 60 percent effective for the strains they contain.

Thomas Frieden, the Centers for Disease Control and Prevention director, said Thursday that he's more optimistic that this year's vaccine will be more effective. “It doesn’t matter which flu vaccine you get, just get one,” he urged.

The vaccine has already been shipped to many pharmacies, doctor's offices and other locations. The CDC recommends vaccination for children six months of age or older. Public health officials especially urge young children, people over age 65 and those with chronic health conditions to get a shot.

This year there are a myriad choices in how you can get your vaccine, which typically cost between $32 to $40, but are covered by many health insurance carriers without a co-pay.

  • There is the normal trivalent or three-strain shot and a stronger quadrivalent or four-strain shot.
  • There's also a nasal spray that can be used in those who are healthy and ages 2 to 49. If you have asthma or other some other conditions, doctors recommend you don't use the spray.
  • If you're squeamish about needles, you may want to try out a new device called a jet injector that can deliver the vaccine through your skin without a needle. But it's not for kids or seniors.
  • There's also an intradermal version that users tiny needles and is supposed to be less painful.
  • For those allergic to chicken eggs there's a special version for you.
  • And for those who are 65 and older, a super vaccine with higher doses.

Developing a universal flu vaccine that protects against all strains and can be given once every few years or once in a lifetime is a major priority for the National Institutes of Health. Earlier this year, researchers said they had made some strong progress towards that goal but it was only in animal models and it could take several years or more to figure out whether the work they did can be translated to humans.

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