Health Promotion and Disease Prevention
Domain 2: Health Promotion and Disease Prevention
This domain tests how health professionals prevent disease and promote health at individual, community, and population levels. Items ask you to classify a prevention activity, judge whether screening is justified, apply immunization and nutrition guidelines, or identify where to break the chain of infection.
Levels of prevention
- Primary: prevent onset before disease occurs-immunization, fluoridated water, health education, seat belts, condoms.
- Secondary: detect and treat early, in the preclinical phase-Pap tests, mammography, colonoscopy, blood pressure and TB screening.
- Tertiary: limit disability and complications after disease-cardiac rehabilitation, diabetes self-management, physical therapy.
- Quaternary (less commonly tested): avoid unnecessary intervention and overdiagnosis.
Screening and immunization
- Screening is justified when the condition is important, has a detectable preclinical phase, the test is acceptable and accurate, early treatment improves outcomes, and benefits justify costs and harms (false positives, overdiagnosis).
- Live attenuated vaccines (MMR, varicella, intranasal influenza) are generally contraindicated in pregnancy and severe immunocompromise; inactivated vaccines are preferred there. Herd immunity protects those who cannot be vaccinated; thresholds vary by pathogen (measles is very high, ~95%).
- Notifiable diseases are reported to public health authorities.
Nutrition and physical activity
- Dietary Guidelines for Americans, 2020–2025: limit added sugars to <10% of calories, saturated fat to <10%, sodium to <2,300 mg/day; choose whole grains, fruits, vegetables, lean proteins, and low-fat dairy. MyPlate: half the plate fruits and vegetables.
- Adults: 150 minutes/week moderate or 75 minutes/week vigorous aerobic activity plus muscle strengthening on 2 days. Youth: 60 minutes/day of moderate-to-vigorous activity.
Communicable disease control
- Chain of infection: agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host. Interventions target any link-hand hygiene, vector control, isolation, vaccination.
- Sexually transmitted infections: consistent condom use, testing, partner notification, HPV and hepatitis B vaccination.
Worked example
A district proposes three programs: (1) HPV vaccination for 11–12-year-olds, (2) annual FIT testing for colorectal cancer at age 45, (3) cardiac rehab after a heart attack. Classify each. HPV vaccination is primary-it prevents infection and cancer before onset. FIT testing is secondary-it finds preclinical cancer or polyps in asymptomatic people. Cardiac rehab is tertiary-it reduces complications and improves function after disease is established. Reasoning: the level is set by the target population's disease stage, not by the setting or who delivers the service.
Traps that cost marks
- Labeling screening as primary prevention.
- Applying adult 150-minute activity guidelines to children.
- Assuming a vaccine is live because it is injected; route does not determine type.
- Ignoring false positives and overdiagnosis in screening decisions.
- Forgetting that herd immunity protects unvaccinated people, not just vaccinated ones.