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Levels and strategies of prevention
Prevention is divided by the stage at which one intervenes – preventing the risk factor itself, preventing the disease, early detection, limiting harm in the patient and preventing harm from overtreatment – and by strategy: shifting the whole population a little, or treating the high-risk group intensively.
Why it matters in the exam
Items on this topic describe an action and ask which level of prevention it belongs to: vaccination, seat belts or water fluoridation – primary prevention; mammography, a faecal occult blood test or blood pressure measurement – secondary prevention; cardiac rehabilitation or diabetic foot care – tertiary prevention; policy that stops risk factors from arising in the first place, such as urban planning that encourages walking – primordial prevention; and avoiding unnecessary tests and treatments – quaternary prevention. Other items deal with Geoffrey Rose's "prevention paradox": most cases come from the majority at moderate risk, so an intervention that shifts the whole population a little prevents more cases than treating only high-risk people – but the benefit to each person is small. Also tested are the advantages and drawbacks of the two strategies, and the prevention of non-communicable diseases: four main behavioural risk factors – tobacco, unhealthy diet, physical inactivity and harmful use of alcohol – which the World Health Organization places at the base of its global action plan. Remember that the same action can sit at different levels depending on context – treating hypertension is primary prevention of stroke, but secondary prevention of the hypertension itself when it is found on screening.
Key points
- Five levels: primordial, primary, secondary, tertiary and quaternary.
- Screening is secondary prevention.
- The prevention paradox: a small intervention across the whole population prevents more cases.
- A high-risk strategy gives a large individual benefit to a few.
- Four main risk factors for non-communicable diseases: tobacco, diet, inactivity and alcohol.
Summary table
| Level | Aim | Example |
|---|---|---|
| Primordial | Prevent risk factors from arising in the population | School food policy, urban planning for walking |
| Primary | Prevent disease onset in healthy people | Vaccination, seat belts, water fluoridation |
| Secondary | Detect disease at a latent stage and treat early | Mammography, faecal occult blood test, blood pressure check |
| Tertiary | Reduce complications and disability in patients | Cardiac rehabilitation, diabetic foot care |
| Quaternary | Prevent harm from unnecessary treatment and tests | Avoiding needless imaging in simple back pain |
| Population versus high-risk strategy | Shift the whole distribution or treat the tail | Reducing salt in food versus drug treatment for people with high blood pressure |
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Sources
- Rose G, Sick individuals and sick populations, 1985 — International Journal of Epidemiology – population and high-risk strategies
- Last (ed.), A Dictionary of Epidemiology (Porta), 6th ed., 2014 — Prevention – primordial, primary, secondary, tertiary, quaternary
- WHO, Global action plan for the prevention and control of noncommunicable diseases, 2013–2030 extension — Risk factor reduction
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.