I have three strictly indoor cats - 2 purebred Siamese and one young "alley cat" . I used to give my older cats -- who have all passed on now --- every conceivable vaccine on the planet "just in case" though none of them ever set foot outside. I've gone now almost 180 degrees the other direction.
In PA, we have to vaccinate for rabies. The only other vaccine I'm allowing for now this the four vaccine combo that's distemper and the URI stuff. But I've read a number of articles that say the immunity from these last much longer than one year, so there is really no need to re-vaccinate every year, especially if your cat never goes outside. I was going to skip the yearly booster for the Siamese this year, but in light of bringing in little Gypsy and knowing how many bugs kittens can carry, I decided to go ahead and do it this year, but I may stop vaccinating for anything except rabies.
Also, I don't know what type of cat you have, but it seems that the oriental breeds are FAR more sensitive to vaccines and prone to bad reactions from them than many others. Some Siamese breeders I have talked to do not vaccinate at all because of the amount of "vaccine shock" cases they've had. In fact, Jango (one of the Siamese brothers) got very sick one week after being vaccinated this year, and I can't help but think that's not a coincidence.
Just my opinion.......