Which of the following is used for passive immunization?

AIIMS Raipur - 2017 (Shift-3)

Applied Microbiology & Infection control

Easy

Appeared in: AIIMS Raipur - 2017 (Shift-3)

Explanation

Passive immunization is the administration of pre-formed antibodies, providing immediate but temporary protection.
Human and animal sera are rich sources of these ready-made antibodies (immunoglobulins or antitoxins).
This method is used for post-exposure prophylaxis, where immediate protection is crucial, such as after a rabies bite or tetanus-prone wound.
Unlike vaccines, passive immunization does not stimulate the host's immune system to produce memory cells, so the protection is short-lived.

Option B: Killed vaccines consist of microorganisms that have been inactivated. They cannot cause disease but still contain antigens that stimulate the recipient's immune system to produce their own antibodies.
Option C: Toxoids are bacterial toxins that have been modified to be non-toxic but still antigenic. They stimulate the body to produce antitoxin antibodies.
Option D: Live attenuated vaccines contain a weakened (attenuated) form of the live virus or bacteria. They multiply in the body to a limited extent, inducing a strong and long-lasting immune response.

Visual 1: Diagram: A flowchart comparing the pathways of Active Immunity (exposure to antigen -> body produces antibodies) and Passive Immunity (direct transfer of antibodies).
Visual 2: Infographic: A table listing examples of conditions requiring passive immunization (e.g., Rabies, Tetanus, Diphtheria, Snakebite) and the corresponding immunoglobulin/antiserum used.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Passive vs. Active Immunization as background academic context rather than a clinical decision trigger.
Nurses must understand the difference between active and passive immunity to manage post-exposure prophylaxis effectively. For example, a patient with a tetanus-prone wound who has an unclear vaccination history may receive both Tetanus Immunoglobulin (passive) for immediate protection and a tetanus toxoid vaccine (active) for long-term immunity.
Passive immunization is a critical intervention for immunocompromised patients who cannot mount an adequate response to a vaccine.
What if a pregnant woman is exposed to Varicella (chickenpox)? Since live vaccines are contraindicated in pregnancy, she would be a candidate for passive immunization with Varicella-Zoster Immunoglobulin (VZIG) to prevent or modify the infection.

How to Approach the Question

Identify the key term in the question: "passive immunization".
Recall the definition of passive immunization: receiving pre-made antibodies from an external source for immediate, temporary protection.
Evaluate each option based on this definition.
Option A (Human/animal sera): These are sources of pre-made antibodies. This matches the definition.
Options B, C, and D (Killed vaccine, Toxoid, Live attenuated vaccine): These are all types of immunizing agents that stimulate the body to create its own antibodies. This is the definition of active immunization.
Conclude that human and animal sera are used for passive immunization.

Concept Tested & Keywords

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