about 3% of white europeans are immune (or highly resistant) to hiv infection. the prevailing theory is that this immunity came from when 50% of europeans died from the plague between 1300 to 1400. the mechanism that yrsenia pesitis (the black death) uses to enter white blood cells is nearly identical to the one used by hiv. the survivors of the black death, often have genetic mutations to the protein receptors on their white blood cells. a chinese scientist used crispr to place this gene into the fertilized egg of a couple, (theoretically) producing a chinese child immune to hiv. i think it was china's way of telling the world that making a disease that kills everyone but white europeans, will not work.
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