What factor might increase a person’s susceptibility to infection by pathogens?

What factors might increase a person’s susceptibility to infection by pathogens?
Answers:
Poor immune system, malnutrition, chronic physical illness, such as kidney failure, etc.
exposure to pathogenetic organism (obviously). amount of pathogen youre exposed to (dose). virulence of infecting agent. strength of your immune system. previous vaccination/immunity.
Already ill (such as cold or something), chronic illness (such as CF), medically compromised immune system (AIDS for example), poor nutrition, within are bunches.

Related Questions:
What does the hospital do near adjectives the departed over body parts, abort babies, blood etc?   How have Adderal artificial you?   Is here something that a doctor can prescribe to me to increase my appetite?   7 days within a week...52 weeks contained by a year..7 X 52 is 364...where on earth does the other daylight come from?   Can i become a doctor!?  
  • Do you reject leaky specimens received to the laboratory?
  • Preservation of late bodies surrounded by different climates?
  • How heaps doctors are out near surrounded by the U.S.?