Pathogen design is reaching a level where it might be feasible to target it against a single physical trait.
Like: if no proper encoding found in the RNA for insulin producing cells, induce some pancreas cells to produce insulin.
Or: if blood cell presents AB+ markers, induce apoptosis.
There are over 40 blood type types identified so far, and new ones keep getting added… plus hundreds of other types of cell markers… which should let one create a genocidal pathogen against a very closely delimited population (plus some collateral damage, but when has that stopped anyone?).