A.P.
I know you can have a religious objection, even if you don't. The doula I worked with for my son's birth does this. Her children are in public school, and are not immunized. She said you can claim a religious objection, but that it is illegal for the state to question and ask what religion you are. So that may be a work-around. I asked my chiropractor--her kids are not vaccinated, but are not yet in school. She said there is a "religion" that was started by chiropractors exactly for this reason. Their only "belief" is not to put anything into the body or take anything out. She said you send in $25 and they send you the paperwork for the "church." I believe this link is what I'm talking about...of course to go that route, you'd probably have to be against all immunizations, not just the flu shot...
http://query.nytimes.com/gst/fullpage.html?res=9E01E5DA15...