The person's health status fluctuates continually, varying from being in good health to becoming ill and returning to being healthy. To understand the concept of illness prevention, there are two models. First, the health-illness continuum model is a graphic representation of an individual's wellness. It states that a person is considered healthy in the absence of physical disease and the presence of good emotional health.

The agent-host-environment model states that disease results from interacting with the agent and the susceptible host in an environment. In this triad model, the agent is what causes the disease, the host is an organism, usually a human or an animal, that harbors the disease, and the environment is the surrounding area that causes or allows disease transmission. To successfully adapt to a chronic illness, the person must learn to live as normally as possible and maintain a positive self-concept and sense of hope. The person must also recognize what they can control and what they cannot control in their own life.