3 Prevention and Health Promotion
Learn how prevention is timed across the course of illness, how screening should be designed and evaluated, and how health promotion and population-wide strategies support healthier communities.
How prevention supports health
Prevention and seek to protect and improve health before illness occurs, detect problems early, and reduce the effects of disease. They operate at individual, community, and societal levels. Effective approaches can combine personal services, such as vaccination or , with supportive environments and policies that make healthier choices more accessible.
Levels of prevention
The primary, secondary, and tertiary framework classifies prevention by the stage of a disease or injury. These levels describe an intervention's purpose and timing, not necessarily where it takes place.
acts before disease or injury begins by reducing exposure to causes or strengthening protection. Examples include immunization, tobacco-control policies, safer road design, and access to nutritious food.
seeks to find disease early, often before symptoms appear, and act to limit its progression. An example is an eligible, asymptomatic population, followed by diagnostic assessment and appropriate care.
aims to limit complications, disability, or recurrence after a condition is established. Examples include rehabilitation after a stroke, treatment to prevent complications of diabetes, and support for long-term disease management.
The levels can occur in the same setting: a clinic may provide through vaccination and through . Prevention activities can also overlap. For instance, managing a chronic illness may help prevent complications while promoting a person's overall well-being.
and supportive conditions
is the process of enabling people to increase control over and improve their health. It is broader than giving health advice because it also addresses the social, economic, and physical conditions that shape people's choices and opportunities.
Approaches can include health education, community participation, supportive public policy, and changes to schools, workplaces, neighborhoods, and health services. For example, encouraging physical activity is more feasible when communities also have safe sidewalks, parks, and accessible recreation spaces. Combining information with supportive environments can help people act on what they know.
Equity is important when designing a program. Consider who can access it, who may face barriers, and whether it improves or worsens gaps in health.
and its trade-offs
uses a test or assessment to identify a possible health problem in people who do not have recognized symptoms. It is a form of , not a diagnosis. A positive result generally means that further evaluation is needed; it does not by itself confirm disease.
A sound program should:
Define the population it targets and use evidence to determine who is likely to benefit.
Use a test whose accuracy and practical limitations are understood.
Provide timely follow-up, diagnostic testing, and access to effective treatment when indicated.
Weigh expected benefits against harms and burdens.
Review results and update the program as evidence and recommendations change.
can detect disease earlier, but it can also lead to false-positive results, anxiety, unnecessary follow-up tests, overdiagnosis, or overtreatment. More is therefore not automatically better. Decisions should follow current guidance for the specific condition and population and, when appropriate, include discussion between patients and clinicians.
Population-wide approaches and equity
A aims to improve health across a group or community, rather than focusing only on people already identified as being at high risk. It may combine several approaches:
Policy and environmental change: smoke-free rules, clean-air protections, or safer streets.
Community programs: locally designed health education or accessible physical-activity opportunities.
Preventive services: making vaccination or evidence-based easier to obtain.
Partnerships across sectors: coordinating public health agencies, health-care providers, schools, employers, and community organizations.
Population-wide measures can reach many people, while targeted programs can direct additional support to places or groups with greater health burdens or access barriers. Local data can help select and assess interventions and align resources with need. Programs should track reach, outcomes, and differences across groups so that improved average health does not conceal widening disparities.