I am not anti vaccine
I do think that a lot of parents would like a bit more help in making the decision (and it is a big decision for some) than "do it or your child will suffer serious side effects from very nasty diseases". The problem with that argument is that most children recover perfectly well from measles mumps and rubella with no side effects at all in exactly the same way as most children have absolutely no problems with the vaccine. Adverse events are a tiny minority on both sides of the fence.
Many parents are very worried about environmental toxins too, that is why they go out of their way to find products (shampoo, deodorants, moisturisers and household cleaning products) that are free from potentially harmful ingredients. That is why they buy and grow organic food and don't eat food such as tuna. It is not possible to avoid toxins completely but it is possible to reduce them in many instances.
It is hard to make rational choices when there is obviously so much emotion on each side. OP you need to do as much research as possible but this is a volatile subject to start on MN.
Personally I need to know both sides before I make a choice and the more I'm told to just follow advice the more I'm inclined to dig my heals in. Take your time, nothing bad will happen if you delay the vaccine by a week or so while you do your research. Talk rationally to your GP, I got some very good, non biased, advice from mine.
I have made my choices in this regard- I made it based on the evidence I could find, discussions that I had and also knowing my children and what was best for them as indeviduals. I'm perfectly comfortable with the choices that I have made. Some would agree with me others would disagree, that's just the way things are.