Getting a flu vaccine is a civic duty
Is this your personal opinion or some official policy?
(1) The flu vaccine is around 70% effective.
Do you have the reference? Medical research is often biased/flawed. The medical researchers I know are horrible in correctly interpreting their data, and I think there is an interest in keeping it that way because it makes it so much easier for the drug companies to request papers that praise their products without compromising the researcher's ethics too much.
I am asking because here (Argentina) the shot is only indicated (and as such, given for free in hospital) for people in a risk group: infants, old people, pregnant women and health workers. I am not sure about people working in schools, and I am sure I am forgetting some minor groups (maybe people with HIV can take it?), but you get the idea.
The US seems to have a tendency to use a lot more medications than Argentina. This may very well be because they can afford it more, but I did not get that impression about other developed countries. So, I tend to think there is a lot of overmedication in the US, although this is just a sensation. I would love some counterpoints if you have them.
The risks are essentially zero
There is such thing in medicine, because there is a lot of unknown things. Aspirin for instance, was used a lot for many years with no knowledge of its risks on the stomach.