Your vaccine works now. Why do you believe it will work for the rest of your life? While it works against the main COVID-19 variants, it might not work against

Your vaccine works now. Why do you believe it will work for the rest of your life? While it works against the main COVID-19 variants, it might not work against some evolutionary accessible variant. New variants require a non-immune host population for natural evolution to occur. The more people with COVID-19, the more likely there will be some mutation that affects vaccinated people. This is why the flu shot doesn't carry life-time immunity against influenza. Therefore, even if I'm only using egotistical reasoning, my understanding of how vaccines work make me care that others also get vaccinated - it reduces my future chance of health problems.