What about targeted vaccinations and other health interventions for smart kids? I don't think thiis is a good idea, partly because it's going to be so much less efficient than just helping everyone, but you may.

Not at all, that sounds great, if it were possible. Certainly generally effective health interventions sound even far more likely. But if there were a health intervention that only benefited smart kids, I would definitely consider that a net plus as to not having it exist at all.

[ETA] If it imposed some extrinsic cost on everyone else, that would be a different matter, but that's not how vaccines work, is it?