Here's another excellent link on the dangers of feline vaccinations:
http://www.vas-awareness.org/What is VAS Awareness?
“VAS” stands for Feline “Vaccine Associated Sarcoma.” Some also call this disease “Injection Site Sarcoma” or "Vaccine Site Sarcoma". VAS is any of a number of cancers, most commonly Fibrosarcoma, which are believed to be triggered by vaccinations and occasionally other kinds of injections. VAS is primarily an issue for domestic cats, though it has been identified in ferrets and tigers, and recent research indicates that it may also occur in dogs.
Who are we?
The people who make up VAS Awareness come from a group of people who currently have a cat being treated for this cancer or have had a cat that has died as a result of this cancer. We include professionals from the world of business and veterinary medicine. We are not anti-vaccination, but pro-education. We believe that prevention is the best cure for this deadly cancer and that through public education, the incidence of this cancer can be reduced dramatically.