Which is a primary prevention activity?

• A. Vaccination
• B. Mammography
• C. Rehabilitation after stroke
• D. Screening for high blood pressure

Answer: (A)

Primary prevention aims to stop a disease from occurring by preventing its occurrence in the first place. Vaccination does exactly that: it safely exposes the immune system to a component of a pathogen or a harmless form, allowing the body to build immunity so infection is prevented or significantly blunted if exposure happens later. This is different from screening tests like mammography or blood pressure checks, which are secondary prevention because they look for a disease in people who do not yet have symptoms to enable early treatment and prevent complications. Rehabilitation after a stroke is tertiary prevention, aimed at reducing ongoing disability after disease has already caused damage. So vaccination best fits the goal of primary prevention.