What are some unusual immunities that certain people have?

shutterstock

How’s that for academic-speak.

10% of Europe’s population is immune to the HIV virus. The immunity is highest in Scandinavian countries.

There’s a theory that it is tied to the Black Plague.

They found a mutation, CCR5-Δ32, that blocks the virus from entering immune cells. They have dated the mutation directly to the time of the plague.

And the popular theory is that when the plague swept across Europe, killing 40% of the population (let that sink in 40% - this was a time when humans saw the risk of extinction as a very real threat), very few people had the mutation. But those that did - lived on to have children. (Remember evolution is often just a series of mutations that ensures survival. )

The plague had several sweeps, it wasn’t an all at once thing. With each sweep, the CCR5-Δ32 got propagated.

.01% --> .1% --> 1% --> 10%

Until we are where we are today. The proportion of people with the mutation is on the right side of the below image.

(Note that this region is exactly where the black plague hit.)

Of course, today, that 10% number will trend downward as we have medicine to spare us from the many savage iterations of evolution.