Susceptibilitat

Susceptibilitat is the degree to which a system, organism, or population is prone to exhibit a response when exposed to a stimulus or agent. In health and medicine, it refers to predisposition to disease, infection, or adverse reactions. In physics and materials science, susceptibility describes how strongly a material responds to external fields by becoming magnetized or polarized.

In biology and medicine, susceptibility results from an interaction of genetic, environmental, and physiological factors. Genetic predisposition, immune status, age, sex, prior exposures, and comorbidities influence how likely someone is to develop an infection or another condition after contact with a pathogen or trigger. Environmental factors, such as nutrition, stress, and social determinants, also play a role. Examples include higher susceptibility to respiratory infections in older adults, autoimmune diseases in certain genetic backgrounds, and adverse drug reactions in people with specific metabolic profiles.

Assessing susceptibility involves epidemiological data, family history, and, in some cases, genetic or biomarker testing. Population-level susceptibility varies over time with vaccination, exposure patterns, and changes in pathogen virulence. In physics, magnetic susceptibility (χm) measures how much a material magnetizes in an external magnetic field, with M = χm H; electric susceptibility (χe) relates polarization to an external electric field via P = χe ε0 E. Materials are categorized as diamagnetic, paramagnetic, or ferromagnetic, and temperature can influence susceptibility.

Understanding susceptibility aids prevention, screening, and risk communication, and supports personalized approaches while avoiding stigmatization of groups perceived as more susceptible.