Why have I never heard about this before?
The concept and the name are still quite recent. It really started to get more attention in 2014, when Phase 1 of a research initiative called the Human Microbiome Project was completed.
Using the new technique of genetic sequencing, the aim of this program was to get a map of all bacteria living on humans.
The results are fascinating: it is literally a whole new world, right under our nose (and ON our nose, and IN our nose…).