lol I cannot believe on a site based around drug use and abuse with the majority of members at (least) one time taking an unknown substance(s) for pleasure that people could be against the flu vaccine, which is a known substance and has had at least some medical research behind it. You can say that you test pills but that can't tell you all the ingredients and god knows what most coke, meth, H, speed, etc are cut with. Even oxy pills - if you didn't buy them yourself from a pharmacy how can you know that they havent been repressed by a clever dealer (I know this is unlikely- but its still possible, and more possible than having a reaction to a flu vaccine). And yeah if you exeriment with RCs well... its already been well said.
If you have the opportunity to have the vaccine and you spend time around other people then you should take it. For their benefit.