The three levels of prevention are primary, secondary, and tertiary.

In primary prevention, a disorder is actually prevented from developing.

Types of primary prevention include the following:

• Vaccinations

• Counseling to change high-risk behavior

• Sometimes chemoprevention

In secondary prevention, disease is detected and treated early, often before symptoms are present, thus minimizing serious consequences.

Types of secondary prevention include the following:

• Screening programs, such as mammography to detect breast cancer and dual x-ray absorptiometry (DXA) to detect osteoporosis.

• Tracking down the sex partners of a person diagnosed with a sexually transmitted infection (contact tracing) and, if necessary, treating these people to minimize spread of the disease.

In tertiary prevention, an existing, usually chronic disease is managed to prevent complications or further damage.

Types of tertiary prevention include the following:

• For people with diabetes: Control of blood sugar, excellent skin care, frequent examination of the feet, and frequent exercise to prevent heart and blood vessel disorders

• Providing supportive and rehabilitative services to prevent deterioration and maximize quality of life, such as rehabilitation from injuries, heart attack, or stroke

• Preventing complications in people with disabilities, such as preventing pressure sores in those confined to bed.