I'm reminded of the M.A.D.D. campaigns to reduce drunk driving with faked crash scenes in front of schools. They would set up a crashed car with dummy "bodies" strewn (and even scattered blood/glass) across walkways where everyone could see them.
I don't think it was a particularly effective tactic.
I was able to dig up this paper that showed 66% of the COVID unvaccinated regretted their decision after hospitalization. The rest were undeterred, even after hospitalization, mostly due to ideology and conspiracies.
But the problem is that I wouldn’t be comfortable risking public health to prove 2/3 of a point to vaccine skeptics who should’ve known better anyway. The Hippocratic oath is to do no harm, and I wouldn’t want a loved one with a suppressed immune system or lung problems to get seriously sick because we let the disease spread by choice.
The real vectors of disinformation are social media, and antivax deaths are downstream of that.
But we don't have any kind of cultural immunity to the kind of propagandised and designed messaging that drives these campaigns.
In the absence of that, learning through consequences - and coming in with the messaging after they happen - is the only thing that can make a difference.