Which option is an example of primary prevention in public health?

• A. Treatment of existing disease.
• B. Vaccination program.
• C. Rehabilitation after injury.
• D. Palliative care.

Answer: (B)

Primary prevention aims to stop disease from occurring in the first place by preventing exposure or boosting resistance. A vaccination program fits this best because it trains the immune system to recognize and fight specific pathogens, preventing infection and reducing the incidence of disease in the population.

Treating an existing disease handles illness after it has started, which is not prevention. Rehabilitation after injury focuses on restoring function after damage has occurred, and palliative care centers on comfort for those with serious illness, neither of which aims to prevent the disease from developing in the first place.

So, vaccination is the classic example of primary prevention.