Why was the MMR vaccine so controversial?

Answer 1

It's not just MMR. Many parents are very cautious about giving something to a otherwise healthy child. Unfortunately, that's the nature of vaccines. They are to prevent future illnesses. Because of this fact, an effective vaccine would basically eliminate the occurrence of the disease it's made for. As the result, the parents rarely ever witness or experience the actual disease. They will more likely see the side effects of the vaccines. Unfortunately, all medications have side effects, including placebos used during testing. It's these side effects that cause vaccines to be controversial. Some claim that there is direct cause of certain conditions because of the vaccines while the medical communities have repeatedly showed that's not the case. However, many parents are not convinced despite the evidences.