Primary prevention strategies intend to avoid the development of disease. Most population-based health promotion activities are primary preventive measures. Regular health exams and tests can help find problems before they start. They also can help find problems early, when your chances for treatment and cure are better. Active immunization entails the introduction of a foreign molecule into the body, which causes the body itself to generate immunity against the target. This immunity comes from the T cells and the B cells with their antibodies.