While we have a feeling that our 'thought experiment' could bear fruit, we are far from the idea that equivalent expressions by the brain and the immune function point to an axis of both systems. Al-though major players, they also depend on the regulation of the rest of the body. As we focus here rather on a social context, many more factors are to be accounted for.
Shanty-towns, rather than being seen in a dismissive context, may provide clues to historical conditions, a tip off perhaps to update the idea of 'individualistic' immunity. Subjected to all kinds of inward and outward interferences, obviously, a historical approach is complex.
Urban overcrowding, by replacing nomadic life, allowed multiple interacting brains to develop civilization and science. The fact that survival under prolonged siege had been recorded, filthy food and water supply notwithstanding,
suggests that collective immune adaptation may not be out of question either.
Fortunately, experimental evidence in mice and other animal comes in support to our hypothesis of collective immunity. As yet no consensus about immune stimulation or downplaying has been reached, our aim being the possibility of reciprocal immune influence as such.