Which of the following is an example of primary prevention?

• A. Vaccines
• B. Radiographic exam
• C. Pap smear
• D. Scaling and root planing

Answer: (A)

Preventing the onset of disease is the goal of primary prevention. Vaccines fit this goal because they stimulate the immune system to build protection before exposure to a pathogen, so infection is prevented or its impact is greatly reduced. That proactive prevention is what makes vaccines a classic example of primary prevention.

The other options describe activities that occur after a problem is present or detected rather than before it starts. A radiographic exam is used to reveal disease that may already be developing or to screen for pathology, which is a detection approach typical of secondary prevention. A Pap smear serves as screening to find early cellular changes before they become invasive cancer, also secondary prevention. Scaling and root planing is a treatment aimed at managing and removing disease that already exists in the periodontal tissues, aligning with therapeutic care rather than prevention.