Well they have the basics of this vaccine don't they? They don't have to start from scratch so at least there's that?
Also, it's still covid-19. It's still the same virus, just a different variant. People who have the vaccination will still have protection in some form, and it's not like covid actually infects everyone or does damage to everyone.
The actual percentage of people who get ill (as in completely bed-ridden) from this is low. Obviously an even smaller percentage is in risk of hospitalisation. It's still a lot of people, but it's not everybody.