Levels of Prevention

01Conceptual Framework

Understanding levels of prevention requires understanding the natural history of disease, a model developed by Leavell and Clark. This model divides the progression of any disease into two broad phases, and every level of prevention is mapped onto one of these phases. Exam writers build vignettes that test whether you can correctly identify which phase of disease the patient is in and, therefore, which level of prevention applies.

Phase 1: Pre-pathogenesis (before disease onset). During this phase, the individual is healthy but may be exposed to risk factors. The disease process has not yet begun at the cellular or physiological level. Primordial and primary prevention operate here. The goal is to prevent the disease from ever starting.

Phase 2: Pathogenesis (disease has begun). This phase is subdivided into early pathogenesis (the disease is present but may be subclinical or asymptomatic), clinical disease (signs and symptoms manifest), and outcomes (disability, recovery, or death). Secondary, tertiary, and quaternary prevention operate here. The goal shifts from preventing disease to detecting it early, treating it, preventing complications, and protecting against harm from the healthcare system itself.

The connection between pathophysiology and symptoms is the central concept here. Just as you connect a disease mechanism to its clinical presentation, exam writers expect you to connect a phase of disease to the correct level of prevention. A question might describe a patient who is healthy but lives in a community with high smoking rates. That patient is in the pre-pathogenesis phase, and the correct intervention targets risk factor prevention (primordial or primary). If the question instead describes a patient with undiagnosed diabetes found on routine screening, you are now in early pathogenesis, and the correct answer is secondary prevention.

02Classification of the Five Levels of Prevention

03Detailed Breakdown of Each Level

3A. Primordial Prevention

Primordial prevention focuses on eliminating the social and environmental conditions that contribute to disease risk before they arise. This level is the most "upstream" of all prevention strategies. It targets the entire population rather than individuals. The concept was introduced by Strasser in 1978 in the context of cardiovascular disease prevention.

The best way to understand primordial prevention is to think about it as preventing the risk factors themselves from developing. A question about primordial prevention will not mention a patient with hypertension or obesity. Instead, it will describe a policy or community intervention aimed at an entire population where the risk factors have not yet appeared.

Under Indonesian regulation, Upaya Peningkatan Kesehatan (health promotion) includes activities supporting nutritional improvement, environmental health, occupational health and exercise, family health, and disease control. The GERMAS initiative (Gerakan Masyarakat Hidup Sehat), launched in 2017 and continued under the RPJMN framework, is a national-level primordial prevention effort that promotes physical activity, fruit and vegetable consumption, routine health checks, maintaining a clean environment, avoidance of tobacco and alcohol, and use of latrines.

Exam-testable examples of primordial prevention:

• Government policy banning trans fats from food products

• Building bicycle lanes and pedestrian sidewalks in urban areas

• Implementing school lunch programs with nutritional standards

• Regulating tobacco advertising under PP No. 109/2012

3B. Primary Prevention

Primary prevention aims to prevent disease from occurring in individuals who are currently healthy but may be exposed to risk factors. Unlike primordial prevention which targets the population environment, primary prevention often involves direct individual-level interventions.

Primary prevention means taking preventive measures that forestall the onset of illness or injury during the prepathogenesis period, and these preventive measures are usually taken for everyone, not just a select group.

The two pillars of primary prevention are health promotion and disease protection. Health promotion includes health education, nutritional counseling, and lifestyle modification. Disease protection includes immunization, chemoprophylaxis (e.g., giving isoniazid to TB contacts), and environmental modifications (e.g., water sanitation, mosquito nets).

Under Permenkes No. 74 Tahun 2015, disease prevention activities include risk factor control, early detection, immunization, and mass prophylactic medication distribution.

Indonesia's National Immunization Program is the prototypical example of primary prevention. The routine immunization schedule includes Hepatitis B at less than 24 hours of age, BCG and OPV1 at less than 1 month, DPT-HB-Hib, OPV, PCV, and Rotavirus at 2, 3, and 4 months, and continued boosters into school age. The BIAS program (Bulan Imunisasi Anak Sekolah) provides booster immunizations against diphtheria, tetanus, measles, and rubella to school-age children in grades 1, 2, 5, and 6, including HPV vaccination for grade 5 and 6 girls.

Exam-testable examples of primary prevention:

• Vaccination of a healthy infant against measles

• Prescribing chemoprophylaxis (e.g., isoniazid for a close contact of an active TB case)

• Folic acid supplementation in women of childbearing age to prevent neural tube defects

• Distributing insecticide-treated bed nets in malaria-endemic areas

3C. Secondary Prevention

Secondary prevention involves early detection and prompt treatment of disease in individuals who are already affected but may not yet have symptoms. The defining feature is screening: identifying disease at a stage where intervention can prevent progression to symptomatic or advanced disease.

Secondary prevention includes preventive measures that lead to an early diagnosis and prompt treatment of a disease or injury to limit disability and prevent more severe progression of illness or injury.

In the Indonesian context, Posbindu PTM (Pos Pembinaan Terpadu Penyakit Tidak Menular) is the flagship community-level secondary prevention program. Posbindu PTM has proven effective in discovering new cases of hypertension and diabetes that were previously undiagnosed, improving treatment adherence through education and support, and strengthening social capital through the role of trained community health workers (kader) and community nurses. Activities include routine blood pressure measurement, fasting blood glucose, cholesterol screening, BMI calculation, and visual acuity checks at the community level.

Key distinction for the exam: A screening test is NOT the same as a diagnostic test. A screening test is applied to asymptomatic individuals in a target population to identify those who likely have the disease and need further evaluation. A diagnostic test is performed on someone who already has symptoms or a positive screening result.

Exam-testable examples of secondary prevention:

• Performing a Pap smear or IVA (inspeksi visual asam asetat) on asymptomatic women to screen for cervical cancer

• Measuring HbA1c in a 45-year-old with obesity and family history of diabetes (screening)

• Colonoscopy in adults over 50 for colorectal cancer screening

• Contact tracing and sputum examination for close contacts of TB patients

• Newborn metabolic screening (heel prick test)

3D. Tertiary Prevention

Tertiary prevention is applied when disease is already established and symptomatic. The goals are to minimize disability, prevent complications, and improve quality of life through treatment, rehabilitation, and chronic disease management.

Tertiary prevention usually involves treatment, where a person who has suffered one illness or injury is treated with the intention of preventing a worse outcome such as disability or death, or a recurrence of the problem.

In Indonesia, PROLANIS (Program Pengelolaan Penyakit Kronis) is the leading tertiary prevention program, implemented through BPJS Kesehatan. PROLANIS is a chronic disease management program at Puskesmas and is followed by BPJS participants. It focuses on managing established conditions such as diabetes mellitus and hypertension through regular monitoring, medication management, group exercise (senam PROLANIS), education sessions, and SMS-based reminders.

Exam-testable examples of tertiary prevention:

• Prescribing ACE inhibitors to a diabetic patient with microalbuminuria to prevent nephropathy progression

• Post-stroke rehabilitation and physical therapy

• Cardiac rehabilitation after myocardial infarction

• Fitting prosthetics for a diabetic patient after amputation

• Anticoagulation therapy to prevent recurrent deep vein thrombosis

3E. Quaternary Prevention

Quaternary prevention means avoiding unnecessary medical interventions, defined as the actions taken to identify an individual at risk of overmedicalization, to protect them from new medical invasion, and to suggest interventions that are ethically acceptable. In 1986, a family physician named Marc Jamoulle coined the concept of quaternary prevention, with the perspective that clinicians could offer good care without the harm of excessive intervention.

This is the newest and most conceptually challenging level. The concept was integrated into the Wonca International Dictionary for General/Family Practice in 1999. Quaternary prevention is rooted in the principle of "primum non nocere" (first, do no harm). It operates across all phases of the natural history of disease, asking at every step whether a proposed intervention does more good than harm.

Exam-testable examples of quaternary prevention:

• Avoiding routine PSA screening in men over 70 when the risk of overdiagnosis exceeds the benefit

• Deprescribing unnecessary medications in an elderly patient on 10+ drugs (polypharmacy)

• Choosing watchful waiting over immediate surgery for low-grade prostate cancer

• Refusing to prescribe antibiotics for a viral upper respiratory infection despite patient demand

• Implementing antibiotic stewardship programs in hospitals

04Mapping Prevention Levels to the Indonesian Health System Framework

UU No. 17 Tahun 2023 defines Upaya Kesehatan (Health Efforts) as integrated and continuous activities to maintain and improve the health status of the population in the forms of promotive, preventive, curative, rehabilitative, and/or palliative efforts.

Note that the Indonesian framework uses five categories of health effort while the international prevention framework uses five levels. They overlap but are not identical. The exam may test either classification, so knowing this mapping is critical.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The most common way students get questions on levels of prevention wrong is by confusing primary and secondary prevention. The critical discriminator is the patient's disease status at the time of the intervention, not the type of intervention itself. A blood test can be primary prevention (e.g., measuring cholesterol to guide dietary counseling before cardiovascular disease develops), secondary prevention (e.g., screening for occult colorectal cancer), or even tertiary prevention (e.g., monitoring HbA1c in an established diabetic). The test itself does not define the level. What defines the level is whether disease is present and at what stage.

Another frequent trap involves confusing screening with diagnosis. Screening is a secondary prevention activity performed on asymptomatic populations. If the vignette describes a patient who presented with symptoms and was then tested, that is diagnosis, not screening, and falls under curative care, not secondary prevention.

For the Indonesian context, remember that Permenkes No. 74 Tahun 2015 formally divides prevention activities into risk factor control, early detection, immunization, and mass prophylactic medication. Questions may test whether you can classify a given program (e.g., Posbindu PTM = secondary prevention via early detection; BIAS = primary prevention via immunization) into the correct level.

Finally, quaternary prevention is increasingly tested. When a vignette describes a clinician choosing NOT to order a test or NOT to prescribe a medication because the potential harms outweigh the benefits, the answer is quaternary prevention. The principle being tested is the ability to recognize that the best clinical decision is sometimes to do less, not more.