Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Host factor
Introduction
Overview
Host factor is a medical term referring to the traits of an individual person or animal that affect susceptibility to disease, especially in comparison to other individuals. The term arose in the context of infectious disease research, in contrast to “organism factors”, such as the virulence and infectivity of a microbe. Host factors that may vary in a population and affect disease susceptibility can be innate or acquired. Some examples:
- general health
- psychological characteristics and attitude
- nutritional state
- social ties
- previous exposure to the organism or related antigens
- haplotype or other specific genetic differences of immune function
- substance abuse
- race
The term is now used in oncology and many other medical contexts related to individual differences of disease vulnerability.