What is the full form of BCG?

BCG stands for Bacillus Calmette–Guérin. It is a vaccine primarily used to prevent tuberculosis (TB), especially severe forms in children such as TB meningitis and miliary TB. The vaccine is named after its inventors, Albert Calmette and Camille Guérin, who developed it from a live, attenuated strain of Mycobacterium bovis.

Key facts about BCG:

• Composition: The BCG vaccine contains live, weakened bacteria derived from Mycobacterium bovis. Each vial, after reconstitution, contains millions of colony-forming units of the bacteria.

• Administration: The vaccine is given intradermally, usually in the upper arm, shortly after birth. It is often part of the national immunization schedule in countries where TB is prevalent.

• Efficacy: BCG is most effective in protecting children against severe forms of TB. Its efficacy in preventing pulmonary TB in adults is variable, but it remains a critical tool in global TB control efforts.

• Side Effects: Most children develop a small, localized reaction at the injection site, which may ulcerate and heal, leaving a characteristic scar. Serious side effects are rare but may include lymph node enlargement or abscess formation.

• Storage and Handling: The vaccine must be stored between 2°C and 8°C and protected from light. Once reconstituted, it should be used within a few hours and any remaining vaccine discarded safely.

• Contraindications: BCG should not be given to individuals with compromised immune systems, such as those with symptomatic HIV/AIDS, due to the risk of disseminated infection.

The BCG vaccine remains a cornerstone of public health strategies to combat tuberculosis, especially in countries with high disease burden.