What is the route of BCG vaccine?

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This question was previously asked in

SGPGI Staff Nurse Official Paper (Held On: 28 Feb, 2024 Shift 1)

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Answer 1

Correct Answer: Intradermal

Rationale:

The Bacillus Calmette-Guérin (BCG) vaccine is specifically administered intradermally, meaning it is injected into the dermis, which is the layer of skin just beneath the epidermis. This method ensures optimal immune response and reduces the risk of complications.
The BCG vaccine is used primarily to prevent tuberculosis (TB), especially severe forms such as TB meningitis and miliary TB in children. Its intradermal route ensures the vaccine is delivered in a controlled manner, promoting the formation of a localized immune response.
This route is also chosen because the dermis contains a high concentration of antigen-presenting cells, which play a crucial role in initiating the immune response.
The characteristic scar that develops after BCG vaccination is a result of the intradermal injection and the body's immune response to the vaccine. This scar serves as evidence of vaccination in many countries.

Explanation of Other Options:

Intramuscular

Rationale: Intramuscular injection involves delivering the vaccine into the muscle tissue. While this method is common for vaccines such as the hepatitis B or influenza vaccines, it is not suitable for the BCG vaccine because it may not elicit the desired localized immune response and increases the risk of adverse effects.

Intravenous

Rationale: Intravenous injection delivers the vaccine directly into the bloodstream. This route is inappropriate for BCG as it could cause severe systemic side effects and does not allow the localized immune response needed for effective protection against TB.

Subcutaneous

Rationale: Subcutaneous injection involves delivering the vaccine into the fatty tissue beneath the skin. While this route is suitable for some vaccines like the measles-mumps-rubella (MMR) vaccine, it is not recommended for BCG as it may lead to insufficient immune activation and higher rates of adverse reactions such as abscess formation.

Conclusion:

The intradermal route is the most effective and appropriate method for administering the BCG vaccine. This route ensures a localized immune response, minimizes complications, and helps achieve the desired protective effect against tuberculosis, particularly severe forms in young children.