What measures for disease prevention that were used historically should be used today? Why do you think some were discarded as preventive measures?

People with some contagious diseases used to be quarantined. When I was a child, about 1943, I had scarlet fever. Of course, my younger brother caught it from me. My mother, brother, and I were quarantined and couldn't leave the house for six weeks for fear of contaminating others.

I doubt if quarantining is necessary today.

Lepers also used to be quarantined.