What distinguishes active immunity from passive immunity?

Active immunity is characterized by the body's immune response to specific pathogens, either through direct exposure to the pathogen (infection) or through vaccination, which introduces a harmless form of the pathogen to stimulate the immune system. This process prompts the body to produce its own antibodies and memory cells, creating long-lasting protection against future infections by the same pathogen.

In contrast, passive immunity occurs when antibodies are transferred from one individual to another, providing immediate but temporary protection. This transfer can happen naturally, such as when a mother passes antibodies to her baby through breast milk, or artificially, through the administration of antibody-containing blood products.

Understanding this distinction is crucial for appreciating how the immune system functions and the ways in which immunity can be conferred.