The flu shot is certainly problematic with an absolute benefit ranging from 1% to 3% depending on the amount of flu in circulation and the vaccine match.  It is also less effective in the young and in the elderly.

It's use should be selective; it would be worthwhile considering if you work in a environment where exposure to the virus is frequent.  Certainly the advice that everyone should get the shot diverts monies from the health care system where it could be better spent.

Interestingly the Globe published an article a couple of months ago to discredit the use of vitamin d supplements to prevent the flu.  Given that the absolute benefit was 2%, not very different from that of the flu shot, you might conclude that the article was severely biased.

The evidence of vaccination efficacy for childhood illnesses is very robust however because big pharma has been shown to consistently distort benefit in the pursuit of profit people are becoming mistrustful.