While the world is currently enduring it’s most recent pandemic with Covid-19, it is interesting to look back in time at how we coped, and what we learned, from previous pandemics.
In the 14th century, the Black Death (or plague) killed around a third of the population of Europe.
As horrible as that was, it apparently also made 10% of Europeans immune to another deadly virus – HIV (although some scientists give the credit to smallpox instead arguing that the plague was not in fact a virus and could therefore not provide a trigger for possible immunity). Notwithstanding, at some point in time a genetic mutation (known as CR5-A32) created a virus-blocking immune-defence in humans that would later (much later!) be found to be effective in some people against HIV.
How? Well, there is a growing body of scientists that think that this genetic mutation has been around for around 2,500 years. This is when Darwin’s theory of evolution and ‘survival of the fittest’ gets real. Over many centuries outbreaks of a virus (more than one) killed people who did not have this mutation, leaving a higher proportion of those with it to live on and reproduce. As this process repeats in generation after generation, the mutation becomes more common. While it is estimated that 1 in 20.000 people had the mutation 2,500 years ago, scientists believe that now 1 in 10 people have it.