Which statement best describes active immunity?

Which statement best describes active immunity?

• A. Active Immunity
• B. Immunity after infection or vaccination
• C. Passive Immunity
• D. Innate Immunity

Answer: (B)

Active immunity is the immune system’s specific defense that develops after exposure to an antigen, either through natural infection or vaccination. When the body encounters a pathogen or receives a vaccine, the adaptive immune system activates B and T cells that recognize particular antigens, leading to antibody production and the creation of memory cells. This memory enables a faster and stronger response upon re-exposure, providing long-lasting protection. That’s why the description “immunity after infection or vaccination” best captures active immunity: it reflects the body generating its own targeted, lasting defense in response to an antigen. In contrast, passive immunity is when antibodies are acquired from another source and provides immediate but temporary protection without forming memory, and innate immunity is the non-specific first line of defense that does not create lasting memory.

Active immunity is the immune system’s specific defense that develops after exposure to an antigen, either through natural infection or vaccination. When the body encounters a pathogen or receives a vaccine, the adaptive immune system activates B and T cells that recognize particular antigens, leading to antibody production and the creation of memory cells. This memory enables a faster and stronger response upon re-exposure, providing long-lasting protection. That’s why the description “immunity after infection or vaccination” best captures active immunity: it reflects the body generating its own targeted, lasting defense in response to an antigen. In contrast, passive immunity is when antibodies are acquired from another source and provides immediate but temporary protection without forming memory, and innate immunity is the non-specific first line of defense that does not create lasting memory.