Which type of adaptive immunity is provided by vaccines?

• A. Artificially acquired active immunity
• B. Naturally acquired passive immunity
• C. Naturally acquired active immunity
• D. Artificially acquired passive immunity

Answer: (A)

Verified step by step guidance

1. Understand the two main types of adaptive immunity: active immunity, where the body produces its own antibodies and memory cells, and passive immunity, where antibodies are received from an external source without the body producing them.
2. Recognize that 'naturally acquired' immunity occurs through natural exposure to pathogens or maternal transfer, while 'artificially acquired' immunity results from deliberate medical interventions such as vaccines or antibody injections.
3. Identify that vaccines work by introducing an antigen (a weakened or inactivated pathogen or its components) to stimulate the body's immune system to produce its own antibodies and memory cells without causing disease.
4. Since vaccines stimulate the body's own immune response, the immunity they provide is classified as 'active' because the body actively produces the immune components.
5. Because vaccines are administered intentionally (not through natural exposure), the immunity they confer is 'artificially acquired active immunity.'