There are many reasons, some more significant than others. In order it would probably look something like this.
1. I believe that Nature created our bodies in a way designed to combat illness and that interferring with that via immunizations seriously compromises the way our bodies were designed to work.
2. I do not believe that most VPD's are "scary" or automatically life changing or fatal. With proper hygeine and nutrition, as well as common sense and available medical treatment, I believe that for most people these diseases are not a real concern.
3. The inbreeding of vaccine makers and people in key places of policy decision making power raises far too many red flags for me to consider any recommendations from those sources as valid. Likewise the refusal to acknowledge any possibility for serious side effects as well as the vaccine manufacturer's "immunity status" from lawsuits raises more concerns.
4. The ingredients in vaccines are not things that were meant to be injected into the human body and have a very real potential for disaster.
5. The potential for disaster has not been adequately researched.
6. Secondary and cross contamination from the vaccine incubation procedures is rarely acknowledged and seldom studied - another potential for disaster.
7. Vaccines are not proven to be effective. No one knows how long they last, if they'll "take", when they may or may not wear off or how well they work. Many children who receive the chickenpox vaccine, for example, still contract chickenpox.
8. I would not want to be responsible for intentionally exposing other children or adults to VPD's - which can and does happen with the shedding issue of some vaccines.
9. I hate needles and don't like to see my children get shots. (Obviously if points 1-8 did not exist this wouldn't prevent me from providing what I felt to be the best medical treatment for my kids. But it is true - I do hate needles! LOL!)
I think that's all, but I may be leaving some out.
Funny, I haven't seen a lot of people posting about their fears of autism in this thread. Don't y'all know that's the *only* concern non-vaxing parents have? Sheesh people, get with the program