not OP but the alternative strategy is to start conservatively and then relax restrictions rather than pivoting between guidelines.

So in this case I think a more clearer solution would have been to be maximally cautious in the beginning, and then only when you're certain loosen what vaccines to apply when. The same way the British handed lockdowns. They started strict, only relaxed measures slowly, and made clear they won't reimpose stronger measures once lifted.

This is understandable to people because there is reassurance and clarity about how to proceed. Which is important because everything else destroys confidence.

But… what restrictions are you suggesting? There was one major restriction right from the start; many countries didn’t allow AZ for over 65s for a while, due to deficiencies in the first trial (and that one usually was dropped). But all other current restrictions are as a result of later discoveries.