[Retric]

The entire point of such vaccinations would be to prevent another major shutdown from a new coronavirus outbreak, and thus avoid a much larger issue when trying to cross borders. The expectation is nobody is going to care much if people get the next shot anymore than they do about the annual flu vaccine because significant herd immunity will be in play.

The only way that changes is if some new and extremely deadly variant is out there, but again past vaccinations are likely still helpful. Thus, regular vaccination deployment would be a pure win for travelers.