i just went through all of this a few weeks ago and am all set. all you have to do is go to your doctor and request getting a titer for all the things you are sure you have immunity to.
kellogg requires immunity to MMR and tetanus. you do a self-screening for TB (bizarre, but whatev).
i'm sure i got the MMR vaccine as a child, so they just drew a few vials of blood and tested to see that i have the antibodies still in my system (which of course i did). easy peasy.
you're supposed to get a tetanus booster every 10 years so i just went ahead and got that shot. it sucked but not a huge deal. in case you're scared of needles, just know that the actual shot itself didn't hurt at all. i was sore for a few days after with a low-grade fever, that's what sucked for me.
anyway, moral of the story is just go to your doc and explain the situation. if you have already gotten the shots and are just worried about getting them again, they'll do a simple blood test. i don't know about you kids, but i'd *much rather* get blood taken than get a shot. but if you're needle-shy enough to even hate getting blood taken, you're SOL.
oh, and if your school is requiring immunization to things you've never gotten shots for...you're SOL on that too.
fun fun!