It's all about solidarity vs selfishness, group behavior vs freeloading individuality. When you get a vaccine you have a small chance to be sick/to die. You take that risk knowing that the overall health of the population will improve. It's a group behaviour. When I bring my kids to the doctor for their shots, I know I have a very slight chance that I am sacrificing their lives so others can live. It's an important collective decision. Any person refusing collective vaccination should be put aside the group, and pay for 100% of medical costs if he gets sick.
This post amazingly generates much more comments than a Biden Trump debate :D