What is the purpose of a vaccine?

• A. A treatment for existing infections
• B. A diagnostic tool for diseases
• C. A preventative measure against specific infectious diseases
• D. A method to increase susceptibility to infections

Answer: (C)

The purpose of a vaccine is fundamentally a preventative measure against specific infectious diseases. Vaccines work by stimulating the immune system to recognize and combat pathogens such as viruses and bacteria. When a person receives a vaccine, it introduces an inactivated or weakened form of the pathogen or components of it. This provokes an immune response, resulting in the production of antibodies. If the vaccinated individual is later exposed to the actual pathogen, their immune system can promptly and effectively respond, reducing the risk of infection and disease.

In contrast to vaccines, treatments for existing infections focus on managing or curing already contracted diseases rather than preventing them. Diagnostic tools are used for identifying the presence of diseases rather than for prevention. Increasing susceptibility to infections contradicts the goal of vaccination, which is to enhance immunity and protection against diseases. Therefore, the essence of vaccines is found in their role as proactive measures aimed at preventing illnesses before they occur.