Agreed; the germ theory of disease simply says infectious disease X doesn't occur but for some kind of microbe. That is, the x-factor isn't bad air, evil spiri

Agreed; the germ theory of disease simply says infectious disease X doesn't occur but for some kind of microbe. That is, the x-factor isn't bad air, evil spirits, or offending the gods. It's obviously not true that if you get infected by microbe m you will get the disease X. Such claims may be overstated to motivate people to get vaccinated or to practice good hygiene or animal handling. What the author seems to be arguing is that medicine has over-emphasized microbes, and under-emphasized the role of immune system deficits, particularly for diseases where latent infections are common.