Possible outcomes does not mean for certain. I have read the possible side-effects of medication and some could be on 1 person in a million getting such a reaction. My mother reacted differently to meds as others and even birth control pills made her loopy. So should we ban the use of any medications because a tiny minority might have a reaction? The downside of that abandonment is severs illness and even death not to mention spreading it to others.
The first drug was said to be 96% efficient. So out of 100, 4 should have been expected to get sick. Now we have less than one percent and too many are making that sound like the drug is a complete failure. Not very smart in my opinion.