Active immunity is not acquired by which of the following ?
**Core Concept**
Active immunity is a type of immunity acquired through direct exposure to an antigen, either through infection or immunization. This exposure triggers the body's immune system to produce antibodies and immune cells that can recognize and attack the specific antigen, providing long-term protection against future infections.
**Why the Correct Answer is Right**
Active immunity is not acquired through passive immunization, which involves the transfer of pre-formed antibodies from one individual to another. This can occur through administration of immunoglobulin preparations, such as antivenom or intravenous immunoglobulin (IVIG), or through breastfeeding. Passive immunity provides temporary protection, as the antibodies are eventually broken down and cleared by the body. In contrast, active immunity involves the activation of the immune system to produce its own antibodies, resulting in long-term protection.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.
**Clinical Pearl / High-Yield Fact**
It's essential to note that active immunity can be acquired through various means, including vaccination, natural infection, and immune system priming. Understanding the difference between active and passive immunity is crucial in clinical practice, as it affects the choice of treatment and the duration of protection provided.
**Correct Answer: A.**