Human sera given after dog bite to prevent rabies?

AIIMS Raipur NO - 2019 (Shift-2)

Applied Microbiology & Infection control

Easy

Appeared in: AIIMS Raipur NO - 2019 (Shift-2)

Explanation

The administration of human sera after a potential rabies exposure is a form of passive immunization.
This serum, known as Human Rabies Immunoglobulin (HRIG), contains pre-formed antibodies that provide immediate, though temporary, protection against the virus.
The mechanism involves neutralizing the rabies virus at the site of the wound before it can infect the nervous system.
This is different from active immunization, where a vaccine stimulates the body to produce its own antibodies over time.

Option B: A toxoid is an inactivated bacterial toxin used to create vaccines for diseases like tetanus and diphtheria. Rabies is caused by a virus, not a toxin.
Option C: Active immunization refers to stimulating the body to produce its own antibodies, which is achieved with the rabies vaccine, not the administration of human sera (antibodies).
Option D: Immunomodulation is a very broad term for any therapy that alters the immune response. While technically true, 'passive immunization' is the specific and correct immunological term for this procedure.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Types of Immunity and Rabies Post-Exposure Prophylaxis as background academic context rather than a clinical decision trigger.
Understanding the difference between active and passive immunity is critical for nurses administering post-exposure prophylaxis (PEP) for diseases like rabies, tetanus, and hepatitis B.
The nurse's role includes immediate, thorough wound cleansing, correct administration of both rabies immunoglobulin (passive) and the vaccine series (active), and educating the patient on the importance of completing the entire vaccine schedule.
What if the patient had been previously vaccinated against rabies? In that case, they would not receive the human rabies immunoglobulin (passive immunity). They would only receive two booster doses of the rabies vaccine (active immunity) on days 0 and 3.

How to Approach the Question

First, identify the key substance mentioned in the question: 'human sera'.
Recall or deduce what 'human sera' contains in this context. Sera from an immune individual contains antibodies.
Analyze the options based on this fact. The direct administration of antibodies is the definition of passive immunization.
Differentiate this from active immunization, which involves giving an antigen (like a vaccine) to stimulate the body to make its own antibodies.
Eliminate 'Toxoid' as it relates to bacterial toxins, not viruses like rabies.
Eliminate 'Immunomodulation' as it is too general compared to the highly specific 'Passive immunization'.

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