**Question:** Vaccine can be stored at subcentre for:

A. 4°C
B. -20°C
C. Room temperature
D. Refrigerator

**Core Concept:** Vaccine storage requirements depend on the vaccine type and its stability.

**Why the Correct Answer is Right:** Vaccines require specific storage conditions to maintain their potency and efficacy. The correct answer, A (4°C), refers to vaccines that can be stored within this range without requiring refrigeration or freezing. These vaccines typically have refrigeration-sensitive components that may degrade at higher temperatures, such as −20°C (option B) or room temperature (option C). Storing vaccines at room temperature may lead to rapid degradation, while storing them at freezing temperatures may cause the vaccine to lose potency or even cause damage to the vaccine vial.

**Why Each Wrong Option is Incorrect:**

Option B (storing vaccines at −20°C) is incorrect because vaccines with freezing requirements may suffer from loss of potency or structural damage to the vaccine vial when exposed to such low temperatures.

Option C (storing vaccines at room temperature) is incorrect as it fails to maintain the stability of the vaccine, leading to rapid degradation and loss of potency.

**Clinical Pearl:** Different vaccines require specific storage temperatures to maintain their potency and efficacy. Always refer to the vaccine label or storage guidelines for the correct temperature recommendation.

**Correct Answer:** A (4°C)

**Explanation:** Vaccines can be stored at 4°C, ensuring stable storage conditions without the need for freezers or refrigeration. This allows for vaccine distribution in areas without reliable access to cold chains or refrigeration systems. Storing vaccines at 4°C helps preserve their potency and safety, ensuring optimal results when administered to patients.