Requiring immunization is a cost-saving measure for countries accepting travelers. The last thing a poor country needs is richer people coming in, getting sick, and ending up hospitalized all while infecting other people.
And the system has hundreds of years, if not millennia, of history. Before immunization was available, quarantines were mandatory even for people without visible illnesses around the world. It's only in 2020 that the idea of this become controversial and some people acted like it was unprecedented through exposure to echo chambers.
And the system has hundreds of years, if not millennia, of history. Before immunization was available, quarantines were mandatory even for people without visible illnesses around the world. It's only in 2020 that the idea of this become controversial and some people acted like it was unprecedented through exposure to echo chambers.