There are already multiple working vaccines. Why on earth would you even contemplate killing or permanently damaging over a million people, just in the UK alone? Do you really think that 90% of the remaining population will be cool with that and continue to lead a normal life amidst all of this? Even a good fraction of other people in the bottom decile for empathy might waver in their commitment to lead a normal and maximally economically productive life if they are (understandably) worried about the risks this brings to their own well-being.