What involves early detection to halt or reduce the effects of a disease?

The correct answer is secondary prevention, which specifically focuses on early detection of diseases and interventions that can halt or slow their progression. This can include activities such as screening tests (e.g., mammograms for breast cancer or blood pressure measurements) that identify conditions at an early stage when they may be more easily treatable or manageable. The goal of secondary prevention is to minimize the severity of the disease or its complications after it has already occurred but before it advances.

In contrast, primary prevention aims to prevent a disease before it occurs, through measures such as vaccination or health education. Tertiary prevention deals with managing the long-term effects of an already established disease to improve quality of life and reduce disability. Disease prevention is a broader term that encompasses all measures taken to avoid disease, including primary, secondary, and tertiary approaches, but does not focus specifically on the aspect of early detection and intervention that characterizes secondary prevention.