All travel will require vax certs, it’s just that simple. Every European nation and their airlines already have the ground work in place. Expect South America and Asia to follow suit. Want to cruise you have to be one of the immunes, same for international flights bank on it. Having spent 11+ years in the service we didn’t get to go to some parts of the world without jabs. Latin America, Africa and South East Asia all required jabs.
It has already started. SAGA cruise line has initiated it recently, and it will spread to other cruise lines.
SAGA Specializing in over 50 year old passengers you will be previously vaccinated and tested onboard. -Tom