Contagion has been successfully falsified around the so-called spanish flu afaik. Still a good period for medical doctors as the rockefeller influence had yet to spread nation-wide.
If you want to entertain another concept of "illness", think of disease as a process of cleansing the body of toxins. The healthier a lifestyle - food, air, water, exercise, stress, pills, the rarer you'll be ill in the year.
A good confirmation imo about this are countries with beach resorts where hotels dump their sewege directly in the sea water. Coincidentaly the period of so-called summer flu, with diahrea/vomitting. "Summer virus", or what some call the shits, the body basically identifies the excrements from swallowing water while swimming and begins an emergency cleansing - all pathways become exit valves.
In any way, once you convince yourself that contagion is still only a theory, the lack of fear will greatly affect your peace of mind. In essence ideas like terrain theory promote an inner calmness while alopathic medicine basically is an engine of fear. Invisible, highly contagious and unstoppable pathogens everywhere...