By December 2021, it's likely that many of the rich countries of the world will have vaccinated at least 75% of their resident populations. If there are no new major widespread new strains resistant to the current vaccine, then it seems likely borders will loosen significantly over the next 12 months. It would surprise me if Oz, NZ, HK, Taiwan and other countries which are currently super strict continue their current effectively-only-residents-can-enter policy by Jan 2022