[aimhigh]

This year’s batch has been proven to be ineffective against the strain that’s been most common this season.

Flu shots are one source of huge profits. They don't require double blind tests like other medications. There is little evidence of their effectiveness. $$$$$$$$$

[eastexsteve]

This year’s batch has been proven to be ineffective against the strain that’s been most common this season.

Wrong. Flu vaccines are rarely a perfect match, but they don't have to be in order to be effective. Please fee free to read up on the subject at:

http://www.cdc.gov/flu/about/qa/flushot.htm

There is little evidence of their [Flu shots] effectiveness. $$$$$$$$$

I don't know whose biology book you have been reading, but you need to take it back for a refund.