This document discusses primary, secondary, and tertiary prevention in health. Primary prevention aims to prevent disease or injury from occurring in the first place through actions like legislation, education, and immunization. Secondary prevention aims to reduce the impact of a disease or injury by detecting and treating it early through screening and monitoring. Tertiary prevention aims to soften the long-term effects of ongoing illnesses or injuries by helping people manage chronic conditions and improve their quality of life. The document provides examples for each type of prevention and emphasizes that intervening further upstream and preventing problems initially is generally more effective.