Which type of immunity is acquired through infection or vaccination?

Active immunity is developed when an individual's immune system is exposed to a pathogen, either through an infection or through vaccination. In this process, the body produces specific antibodies and memory cells that provide long-lasting protection against future infections by the same pathogen.

When a person is infected with a virus or bacterium, their immune system responds by recognizing the pathogen, activating immune cells, and ultimately generating antibodies that can neutralize the pathogen. Similarly, vaccines introduce a harmless part or a weakened form of the pathogen to the immune system, allowing it to learn to recognize and combat the real pathogen without causing disease.

This form of immunity is robust and can lead to long-term protection because the body retains a memory of the pathogen, enabling a quicker and more effective response if re-exposed to it in the future.

In contrast, innate immunity refers to the body's first line of defense that is not specific to a particular pathogen, while passive immunity involves the transfer of antibodies from one individual to another, providing temporary protection. Nonspecific immunity is a broad category that includes various mechanisms that do not target specific pathogens, thus making active immunity distinct in its targeted and long-lasting nature.