At the cost of how many lives? And if the vaccine is successful how would that harm buy-in? If not then it's a failed experiment (though obviously the PR impact could be rather negative!)

I think it's pretty clear from the past year that we need different tools and approaches to dealing with pandemics. One part is clearly faster vaccine development (mRNA seems very promising for this) and pre-emptive vaccine development, another might be permitting very much informed consent take up early on.