There's nothing particularly interesting about self-ownership in your argument, here. It's also pretty sloppy, because thinking in terms of utility is not as straight-forward as you make it. For one, if forced vaccinations led to social upheaval and backlash, that could be argued to have net negative utility, that detracts from the rule utilitarian argument you're making about saving lives. We're also really far from the metaphysics of self-ownership now.