The immune system, let alone the body, is a highly complex system. We really don't have any way to know what hacking the immune system with a vaccine does. It may help us avoid condition A but opens up to conditions B,C,D.

The dilemma is that there is a huge profit motive for addressing A, while B,C,D is a cost borne by the individual and their family/support system.

Ironically, if you care about vaccines, the best thing you can do is create a strong and trusted regulatory framework around them so the profit motive accruing to private parties does not overtake them and destroy public trust, as is happening now.