The Delta 32 genetic mutation prevents HIV; it's been found in the DNA of those who didn't get this Medieval scourge
The mutation prevents the HIV virus from entering the cells of the ... "How Horrors 
of the Plague Made Europe Safer from AIDS Scourge," ... [The gene works] by 
locking out viral infections as they try to enter ... What they found was a mutation 
called CCR5-delta 32.