When you consider vaccinating a cat for other than rabies or distemper, which are high success-rate vaccines that can be given every 3 years, you should do your homework. For example, the FLV vaccine only provides 70% protection, yet may have more side effects. The new FIV vaccine is even worse;and the cat will always test positive for FIV. This is off the Wyeth (Dodge Animal Health Division) web site.

FIP is particulary difficult since, like human flu, it's a bunch of different viruses. Some are completely harmless, others are very nasty. The tests that exist today can't really tell if a cat has FIP. It's usually circumstantial. The best way to avoid any sickness is careful introductions and monitoring all pets in the household.

Sorry I ran off a bit there, but I foster, and had a ringworm scare once and an untested unvaccinated cat running around that I had been first told was tested, etc. It turned out he was oK and had passed his isolation without any sniffles, etc.