For those who can’t have the vaccine, as with other diseases, society does the best to protect them with a functioning health system and we hope fast developments in treatments.
For those who choose not to have a vaccine, that is their right, each individual has the right to choose what preventative medicine or treatments they are willing to accept. In the event that an individual who has chosen not have a vaccine becomes ill with Covid, we look after them with a functioning health system as any civilised society must.
As society, we can try to persuade people to have a vaccine, if they are able to, but we cannot compel them to do so, either literally forcibly or by imposing restrictions on an individuals freedom to such an extent that they have no other choice.
If other countries choose to impose restrictions on travel, that is a restriction an individual will have to take account of in making their decision as to whether to have the vaccine or not.
The simple position is that we get as many people as we possibly can vaccinated voluntarily and then we open up. Covid is not the infectious disease which ends society as we previously knew it, just as other infectious diseases did not end society as known in past centuries. Human beings require social interaction, restrictions cannot last forever.
Regrettably and inescapably that does mean that a number of people (in their thousands) will die each year of Covid, just as people die of flu, malaria, HIV, Ebola etc. worldwide each and every year. But ultimately, we do what we are planning to do, we vaccinate, we treat and we do what we can with all of the medical advancements at our disposal to mitigate that toll as best we can but we don’t achieve anything by turning on our values of being a liberal democracy to compel individuals to make decision that they do not wish to make.