**Core Concept**
The BCG (Bacillus Calmette-Guérin) vaccine is used to prevent tuberculosis, particularly in children. It is administered intradermally and requires proper handling, including the use of appropriate diluents and site preparation.

**Why the Correct Answer is Right**
The BCG vaccine is administered intradermally using a 1:1000 dilution of the vaccine in normal saline or phosphate buffer. The injection site must be cleaned with **alcohol (spirit)** to prevent infection, but the **correct answer is D because spirit (alcohol) is NOT recommended** for cleaning the site. Instead, **antiseptic solutions like 70% alcohol are contraindicated** due to their potential to damage the skin and interfere with the immune response. The WHO recommends the Danish 1331 strain of *M. bovis*, and normal saline is indeed the preferred diluent. Injection is intradermal, not intramuscular.

**Why Each Wrong Option is Incorrect**
Option A: WHO *does* recommend the Danish 1331 strain of *M. bovis* for BCG vaccination — this is true.
Option B: BCG is given **intradermally**, not intramuscularly — this is correct.
Option C: **Normal saline** is the standard diluent — this is accurate.

**Clinical Pearl / High-Yield Fact**
Always use **alcohol or iodine** only for skin disinfection *before* BCG injection, but **alcohol should be applied only after the injection site is dry** to avoid tissue damage. Never use spirit directly on the site — it may cause irritation or interfere with the skin's immune response. The key exam trap is that while spirit is commonly used in other vaccines, **for BCG, the site must be cleaned with antiseptic but not alcohol immediately post-injection**.

✓ Correct Answer: D. Site of injection should be cleaned with spirit