1 Reduce the chances of becoming seriously ill - don't know
2 Reduce the chances of spreading Covid - don't know
3 Protecting the NHS - if 1 is true, then partly. if 2 is true then partly. If 1 and 2 are true, then a bit more than partly. If 1,2,4 and 5 are true, then even more so
4 The vaccine is safe in its present form - don't know
5 The unvaccinated present a risk to the vaccinated - don't know
You may be asking the wrong person. I'm not pro the vaccine...
Also I'm not a scientist, so I can't answer any of the above (and can only guess at 3) and neither can you.