What is the difference between active and passive immunity?

The distinction between active and passive immunity is primarily based on how the immunity is acquired and whether the body produces its own antibodies. Active immunity occurs when the body is exposed to a pathogen or its antigens, leading to the production of antibodies by the immune system. This can happen through natural infection or vaccination. The resulting immunity is often long-lasting because the body creates a memory of the pathogen, allowing for a quicker and more effective response to future exposures.

In contrast, passive immunity involves the direct transfer of antibodies from one individual to another, such as from mother to child through breast milk or via blood products. In this case, the recipient does not generate their own immune response; instead, they are given antibodies that provide immediate protection, but this protection is temporary since the body does not retain memory of the pathogen.

Understanding this key difference clarifies why the correct answer emphasizes that active immunity involves antibody production, while passive immunity does not involve the individual's immune system creating these antibodies. This knowledge is foundational for understanding how the immune system works and the roles of vaccines and maternal antibodies in disease prevention.