Here's a parallel. How do we deal with those who refuse to practise safe sex, exposing themselves and others to the risk of contracting STDs of varying kinds, including lethal HiV and AIDS? Most STDs, too, are not going to kill most people who get them, except for the unfortunate, but they do lead to a lot of misery, which can be ongoing and long-lasting. So does CoVid.
If we are aware of their self-centred blinkers, we refuse to engage in sexual activity with them. If we are aware that our potential fellow-travellers, hairdressers, dentists, beauticians, teachers, nurses have not taken the trouble to make sure that they don't carry and pass on the CoVid virus, we can make sure that they don't breathe all over us. But we can't ask each of them individually, we have to rely on airlines, salons, surgeries, hospitals, schools to check for us.