From Fox News : However, the flu vaccine was reported to be only 10 percent effective against the H3N2 strain, according to USA Today, citing the public health journal Eurosurveillance. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Medical effectiveness is measured in NNT (Number Needed to Treat). With adequate Vitamin D intake, the NNT was 33. This means that one out of 33 people with adequate Vit. D will get the Flu. NNT for this year's Flu vaccine was (at least) 40..... And might be as high as 80, .