Which level of prevention focuses on preventing an injury or illness from ever occurring?

Primary prevention is the correct choice because it involves measures taken to prevent diseases or injuries before they occur. This level of prevention aims to reduce the incidence of health problems by addressing risk factors and promoting healthy behaviors. Examples include vaccination programs, health education, and lifestyle modifications to prevent conditions such as heart disease or diabetes.

In contrast, secondary prevention focuses on the early detection of diseases through screening and prompt intervention to halt progression, such as mammograms for breast cancer detection. Tertiary prevention involves managing and mitigating the effects of existing diseases through rehabilitation and support, helping individuals manage chronic conditions or complications. Quaternary prevention refers to efforts aimed at preventing unnecessary interventions and over-medicalization, ensuring that healthcare is appropriate and not excessive.