just off the top of my head, the polio vaccine initially infected around 20% of the children it was used on with polio. right now we have an opioid epidemic because of a bunch of unethical doctors and pharma pushed opioids for profit. you can also include heroine in this since it was invented by doctors.
doctors used to bleed ppl, shock ppl, lobotomize ppl, treat ppl with urine, use speed for dieting, and prescribe mercury. 100 years from now ppl will probably look back at some of the procedures doctors do now with horror.