Levels of prevention

Preventive healthcare strategies are described as taking place at the primal, primary, secondary, and tertiary prevention levels. Although advocated as preventive medicine in the early twentieth century by Sara Josephine Baker, in the 1940s, Hugh R. Leavell and E. Gurney Clark coined the term primary prevention. They worked at the Harvard and Columbia University Schools of Public Health, respectively, and later expanded the levels to include secondary and tertiary prevention. Goldston (1987) notes that these levels might be better described as "prevention, treatment, and rehabilitation", although the terms primary, secondary, and tertiary prevention are still in use today. The concept of primal prevention has been created much more recently, in relation to the new developments in molecular biology over the last fifty years, more particularly in epigenetics, which point to the paramount importance of environmental conditions - both physical and affective - on the organism during its fetal and newborn life (or so-called primal period of life).

Level	Definition
Primal and primordial prevention	Primordial prevention refers to measures designed to avoid the development of risk factors in the first place, early in life.
Primary prevention	Methods to avoid occurrence of disease either through eliminating disease agents or increasing resistance to disease. Examples include immunization against disease, maintaining a healthy diet and exercise regimen, and avoiding smoking.
Secondary prevention	Methods to detect and address an existing disease prior to the appearance of symptoms. Examples include treatment of hypertension (a risk factor for many cardiovascular diseases), and cancer screenings.
Tertiary prevention	Methods to reduce the harm of symptomatic disease, such as disability or death, through rehabilitation and treatment. Examples include surgical procedures that halt the spread or progression of disease.
Quaternary prevention	Methods to mitigate or avoid results of unnecessary or excessive interventions in the health system

The last of which has often ignored potential negative impacts on human rights and quality of life

Primal and primordial preventionedit

Primal prevention has been propounded as a separate category of health promotion. This health promotion par excellence is based on knowledge in molecular biology, in particular on epigenetics, which points to how much affective as well as physical environment during fetal and newborn life may determine adult health. This way of promoting health consists mainly in providing future parents with pertinent, unbiased information on primal health and supporting them during their child's primal period of life (i.e., "from conception to first anniversary" according to definition by the Primal Health Research Centre, London). This includes adequate parental leave ideally for both parents with kin caregiving and financial help where needed.

Primordial prevention refers to all measures designed to prevent the development of risk factors in the first place, early in life, and even preconception, as Ruth Etzel has described it "all population-level actions and measures that inhibit the emergence and establishment of adverse environmental, economic, and social conditions". This could be reducing air pollution or prohibiting endocrine-disrupting chemicals in food-handling equipment and food contact materials.

Primary preventionedit

Primary prevention consists of traditional health promotion and "specific protection." Health promotion activities are current, non-clinical life choices such as, eating nutritious meals and exercising daily, that both prevent disease and create a sense of overall well-being. Preventing disease and creating overall well-being, prolongs life expectancy. Health-promotional activities do not target a specific disease or condition but rather promote health and well-being on a very general level. On the other hand, specific protection targets a type or group of diseases and complements the goals of health promotion.

Food is the most basic tool in preventive health care. The 2011 National Health Interview Survey performed by the Centers for Disease Control was the first national survey to include questions about ability to pay for food. Difficulty with paying for food, medicine, or both is a problem facing 1 out of 3 Americans. If better food options were available through food banks, soup kitchens, and other resources for low-income people, obesity and the chronic conditions that come along with it would be better controlled. A food desert is an area with restricted access to healthy foods due to a lack of supermarkets within a reasonable distance. These are often low-income neighborhoods with the majority of residents lacking transportation. There have been several grassroots movements since 1995 to encourage urban gardening, using vacant lots to grow food cultivated by local residents. Mobile fresh markets are another resource for residents in a "food desert", which are specially outfitted buses bringing affordable fresh fruits and vegetables to low-income neighborhoods.

Scientific advancements in genetics have contributed to the knowledge of hereditary diseases and have facilitated progress in specific protective measures in individuals who are carriers of a disease gene or have an increased predisposition to a specific disease. Genetic testing has allowed physicians to make quicker and more accurate diagnoses and has allowed for tailored treatments or personalized medicine. Similarly, specific protective measures such as water purification, sewage treatment, and the development of personal hygienic routines (such as regular hand-washing, safe sex to prevent sexually transmitted infections) became mainstream upon the discovery of infectious disease agents and have decreased the rates of communicable diseases which are spread in unsanitary conditions.

Secondary preventionedit

Secondary prevention deals with latent diseases and attempts to prevent an asymptomatic disease from progressing to symptomatic disease. Certain diseases can be classified as primary or secondary. This depends on definitions of what constitutes a disease, though, in general, primary prevention addresses the root cause of a disease or injury whereas secondary prevention aims to detect and treat a disease early on. Secondary prevention consists of "early diagnosis and prompt treatment" to contain the disease and prevent its spread to other individuals, and "disability limitation" to prevent potential future complications and disabilities from the disease. For example, early diagnosis and prompt treatment for a syphilis patient would include a course of antibiotics to destroy the pathogen and screening and treatment of any infants born to syphilitic mothers. Disability limitation for syphilitic patients includes continued check-ups on the heart, cerebrospinal fluid, and central nervous system of patients to curb any damaging effects such as blindness or paralysis.

Tertiary preventionedit

Finally, tertiary prevention attempts to reduce the damage caused by symptomatic disease by focusing on mental, physical, and social rehabilitation. Unlike secondary prevention, which aims to prevent disability, the objective of tertiary prevention is to maximize the remaining capabilities and functions of an already disabled patient. Goals of tertiary prevention include: preventing pain and damage, halting progression and complications from disease, and restoring the health and functions of the individuals affected by disease. For syphilitic patients, rehabilitation includes measures to prevent complete disability from the disease, such as implementing work-place adjustments for the blind and paralyzed or providing counseling to restore normal daily functions to the greatest extent possible.