You can start with How To Raise A Healthy Child ... Inspite Of Your Doctor.
It is easy to read and responsible, written by a pediatrician who used to give vaccinations, Dr. Robert S. Mendelsohn.
May I suggest a book by Paul Offit, head of the CDC, who wrote The Cutter Incident, the true story of an early polio vaccine that gave a little CAlifornia girl polio at the age of 7, Anne Gottschalk, who is now 56 years old and living off and on in a wheelchair today. Her family hired a young attorney, Melvin Belli, who made a reputation for himself with this case and created a legal template for product liability cases to this day. The book is still written in favor of vaccinations, but it shows you how even the pro-vax gang makes huge mistakes.