[viraptor]

> 'we teach our immune system to fight diseases by showing them weaker versions'

This is a simplification of a well researched process which we understand and can read about. What the previous poster wrote was just speculation as far as I can tell, unless someone wants to post some reference about cleaning the brain and blood?

[mxkopy]

https://en.wikipedia.org/wiki/Spleen

"The spleen plays very important roles in regard to red blood cells (erythrocytes) and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron."

[viraptor]

Yes, but what does that have to do with the context here? (I.e. changes triggered by vaccination)