Which stage of disease indicates that an individual is at risk before being exposed?

The susceptibility stage refers to the period before an individual has been exposed to a disease but is at risk of infection due to factors such as a weakened immune system, genetic predispositions, or environmental influences. During this stage, the person has not yet contracted the illness, but various conditions make them more likely to do so if they come into contact with the pathogen.

In contrast, other stages such as the clinical stage, incubation stage, and recovery stage involve the presence of disease. The clinical stage indicates observable symptoms and a confirmed diagnosis, while the incubation stage occurs after exposure but before symptoms appear, and the recovery stage follows illness where the patient is on the path to regaining health. Therefore, the susceptibility stage is uniquely characterized by the risk of potential future exposure and infection without having contracted the disease yet.