Why get vaccinated? Or if you are modern, why get immunity? Answer: to cheat death. "Live your life to the fullest." However, this cliché fails to explain need. 

How do you live your life to the fullest after vaccination? Living your life to the fullest is an insufficient explanation. Other people are deprived of liberty, some are hungry; most of them are unhappy. 

Family relationships, although a better answer, is also an incomplete explanation. We all have varying family situations. 

Why get vaccinated when you have no family relationships? Because we want to "connect our lives" with each other. 

But this desire for connecting is far from "sharing" - it is selfish. We want vaccine to share our lives in order that we do not have to endure pain alone.