Travel vaccine requirements usually only apply to certain nations where certain diseases are a significant risk. For example: Yellow Fever is a high risk in specifically Aruba, Belize, Brazil, Colombia, Costa Rica, Cuba, El Salvador, Honduras and Panama so travel vaccine requirements for that disease are justified but is not a high risk in North America, Europe, Asia therefore travel vaccines for that disease are not required in those regions. Since covid is everywhere about as much as the flu and right now the cases are a lot more mild like the flu, there is no point in having covid travel vaccine requirements for any places.
During the pandemic, lots of nations had strict travel restrictions, vaccine passports and over 80% of the population got fully vaccinated when the vaccines were rolled out but despite this, there was still a high resurgence of covid cases, both the vaccinated and unvaccinated got covid, in fact the majority of covid cases were in the fully vaccinated a lot more than the unvaccinated. That completely refutes the case for vaccine passports.
It's important to note that the vaccines don't stop the transmission of covid, they just reduce the severity of covid, CDC director Dr Rochelle Walensky stated this clearly: https://mobile.twitter.com/cnnsitroom/status/1423422301882748929
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