vaccination is probably the most broadly effective, but there are many ways, big and small, to limit the risks of transmission, so don't fall for the fascist line of thinking that there is only one true way, especially when an understanding of the risks (airborne is highly unlikely) and effectiveness of the various mitigations (no, you never needed masks outside unless tightly packed for extended time) is so woefully lacking.

and civic duty is voting, educating yourself on policy issues, obeying reasonable laws, and tolerating and even celebrating differences of perspective and opinion. it's about participating effectively in our democratic republic. it doesn't encompass every possible responsibility to every other human, like the term 'moral duty' might.