Another Historical Anniversary

It has been 100 years since the 1918 Influenza Pandemic.
An epidemic spread worldwide by soldiers.
An infection that killed vast swaths of people, and changed the genetics of the world forever.

The 1918 flu changed human evolution.   Yes it did.

H1N1 flu is so deadly is because it creates a greater amount of lung damage and activates the immune system more.   It's like getting a horrible rash inside your throat and lungs and intestines.
The flu virus usually resolves in a few days.
But by then the bacterial infections have had a chance to get into the mix.
Especially strep and staph, because the immune system response to those is dampened by the flu virus and subsequent endotoxemia.

The people who died had the strongest immune systems, young men mostly.
They were overwhelmed by the immune molecules, went septic, and drowned in their own lungs.

The people who survived had less robust immune systems.
They were my generation's grandparents.

People with less acute immune reactions are more likely to harbor chronic non-fatal illnesses.
That is most of us.

The evolutionary arc of the microbe/immune interface tends to create chronic debilitating illnesses from acute and lethal germs.

That is the lesson of this story.