What They Are: Vaccines are substances that stimulate the body’s immune system to recognize and fight specific infectious diseases, helping to prevent illness.

How They Work: Vaccines contain antigens—small parts of the disease-causing organisms (like proteins or sugars) or weakened versions of the organisms themselves—that trigger an immune response without causing the disease.

Historical Impact: Vaccination has been one of the most significant public health advances, leading to the near-eradication of diseases like smallpox and a dramatic reduction in cases of diseases such as polio and measles.

Herd Immunity: When a large percentage of a community is vaccinated, it helps protect individuals who cannot receive vaccines (like those with certain medical conditions) by reducing the spread of disease. This is known as herd immunity.

Safety: Vaccines are rigorously tested for safety and effectiveness before being approved for public use. They are monitored continually even after approval to ensure ongoing safety.

Vaccination Schedule: Many vaccines are given according to a recommended schedule, usually starting in infancy and continuing into adulthood. This schedule helps ensure optimal protection against diseases at different life stages.

Economic Benefits: Vaccination can lead to significant economic savings by preventing disease-related healthcare costs, reducing missed work or school days, and improving overall public health.