The first vaccine had a problem where it gave people Lyme every once in a while. My hypothesis is that Lyme disease is an autoimmune disease caused by being exposed too acutely in some way, or for too long. For some people, a tick byte isn’t enough exposure to trigger it. For others, the vaccine is enough. They didn’t catch it early in clinical trials because those people are rare enough to not show up in small studies. So by that logic, the same thing should happen here. Maybe this time it will be a small enough group of people to shove under the rug. There’s no medicine in the world that doesn’t harm people in some capacity.