“On thinking more about that, those countries with higher levels of vaccination and high numbers of infected people may well be encouraging the virus to mutate into some form more resistant to vaccine mediated immunity.”
Exactly, perfect breeding ground for mutations. Although it may be that each further mutation may be attenuated such that it is not lethal, it may still remain highly contagious and cause a high level of morbidity and sequelae such as long covid. And of course the interchange of variants from different countries may result in hybrid variants that are more virulent and more vaccine resistant on the other hand. It really doesn’t look good.