0r it could just be that she was one of those 30% who survive on their own, and the transfusion just speeded things along.
Well, being overly simplistic I will say anything that helps is good. It could make the difference for some people.
Whatever anti-bodies she now has, could help others. That’s a real plus if this is in fact the causal factor.
I would suspect she was much farther along in the infection process when it was first diagnosed. This would mean she was in an infective mode for a considerable length of time prior to diagnosis and isolation. I hope I am wrong.