The primary demographic target is any healthy human being, with emphasis on those 65+. I do not see your point. What I see is the reason why we should not rush out vaccines and drugs without years and years of study. Like other vaccines, we will likely find that a version that provokes a less aggressive response, but will provide some protection will eventually be needed. In trying to produce a universal vaccine in under 9 months, the goal was to protect as many people as possible in the shortest amount of time. We all accepted that problems like this were almost certainly going to happen given the timelines and demands.