Diluent used for dilution of Japanese encephalitis vaccine?

Appeared in: PGIMER NO - 2020

Explanation

The live attenuated Japanese Encephalitis (JE) vaccine (SA 14-14-2 strain) is provided as a freeze-dried powder.
It requires reconstitution with a specific liquid, known as a diluent, before it can be administered.
Phosphate Buffered Saline (PBS) is the correct diluent for the JE vaccine.
PBS is an isotonic buffer that maintains the correct pH and tonicity, which is essential to keep the live virus in the vaccine viable and effective.

Option A: Normal saline is not the correct diluent for the JE vaccine. Using it could affect the stability and potency of the live virus.
Option B: Distilled water is hypotonic and can damage the live virus particles in the JE vaccine through osmotic shock, rendering it ineffective.
Option C: Sodium carbonate is an alkaline chemical compound and is not used as a diluent for any vaccine due to its unsuitable pH and chemical properties.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Vaccine Diluents as background academic context rather than a clinical decision trigger.
Using the correct diluent is a critical patient safety measure. The diluent is specifically manufactured to match the vaccine's requirements for pH, tonicity, and chemical stability.
A nurse must ALWAYS use the diluent supplied with the vaccine by the manufacturer and never substitute it with another fluid like sterile water or normal saline from general stock.
What if? If a nurse mistakenly uses distilled water instead of PBS for the JE vaccine, the hypotonic nature of the water would likely cause lysis (bursting) of the live virus particles, inactivating the vaccine and leading to primary vaccine failure. The patient would not develop immunity.

How to Approach the Question

First, identify the core of the question, which is asking for the specific 'diluent' for the 'Japanese encephalitis vaccine'.
This is a factual recall question common in Community Health Nursing and Pharmacology.
Systematically review the options provided.
Recall or access your knowledge base about the diluents used for common vaccines under the Universal Immunization Programme.
Eliminate incorrect options. You might remember that Normal Saline is for BCG and Distilled Water is for Measles/MMR, which rules out options A and B.
Identify the correct match: JE vaccine is reconstituted with Phosphate Buffered Saline (PBS). This makes option D the correct answer.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) pp. 41-43, 149-151

E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 203-205

Practise the full PGIMER NO - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.