The concentration of the receptor geographically would not be a singular protective effective modality their woefully poor mitigation efforts are legendary, after 800 years gene dilution is going to occur, in fact there is some interest in data mining on this issue. Look at the German and Icelandic paradox and Northern India vs. Southern India, as well as the dearth of cases in Central Asia. Even the high incidence in North American populations of death in African Americans could have a partial genomic explanation.