I have indoor outdoor cats.
When they were just indoor cats (neighborhood not appropriate to letting them outside) I did not vaccinate them. As soon as it became apparent that they could go outside again, (new area) I got all shots up to date before letting them out.
All of them as kittens were given the proper shots. I did not find any negative effect on not giving them shots when they were indoor only.
Rosie - 13
Callie and Tigger, brother and sister - 12
Akira - 2.5
Peanut - 2
Nikko and Spencer, brothers - 3 months