Only Yellow Fever is covered under IHR which are adopted by US law, and people who travel within the Yellow Fever area most definitely have to produce a yellow card (or be vaccinated with a dirty needle at destination).
As soon as travel resumes, you can be sure COVID will be covered as well.
Oh, I agree with you about travel outside the country.
But this idea for travel inside the country or back into public life, or work, or school?
C’mon man this isn’t even an FDA approved vaccine. It is an EUA for the duration of the Covid-19 emergency declaration.