There are many hints that de facto vaccination passports will be announced by President Biden, later this week.
First, there is apparently public support for this:
Second, Biden’s former Covid Czar, Andy Slavitt, when asked about vaccine passports, just last month, said in so many words, “Wait until early September”.
Third, CNN is reporting President Biden will be making his most important speech, so far, on Covid issues later this week.
Biden has favored businesses mandating vaccination of all employees, and businesses and organizations sponsoring events to mandate vaccination of attendees (many already are). Canada has already announced that vaccinations will be mandated for domestic air and rail travel.
Seems likely this is coming to the U.S. very soon.