Last reviewed 2026-04-22 · How we verify

BCG solvent

BCG (Bacillus Calmette-Guérin) is a live attenuated mycobacterial vaccine that stimulates innate and adaptive immune responses to enhance immunological protection.

BCG (Bacillus Calmette-Guérin) is a live attenuated mycobacterial vaccine that stimulates innate and adaptive immune responses to enhance immunological protection. Used for Tuberculosis prevention, Bladder cancer (intravesical immunotherapy), Non-specific immune enhancement in infectious disease contexts.

At a glance

Mechanism of action

BCG is a weakened strain of Mycobacterium bovis that activates both innate immunity (through pattern recognition receptors) and adaptive immunity (Th1 and Th17 cell responses). It has been used primarily as a tuberculosis vaccine and intravesical immunotherapy for bladder cancer, with emerging evidence for non-specific immune enhancement effects in other infectious diseases.

Approved indications

• Tuberculosis prevention
• Bladder cancer (intravesical immunotherapy)
• Non-specific immune enhancement in infectious disease contexts

Common side effects

• Local injection site reaction (erythema, induration)
• Fever
• Lymphadenitis
• BCG-itis (disseminated infection, rare)

Key clinical trials

• The Role of BCG Vaccine in the Clinical Evolution of COVID-19 and in the Efficacy of Anti-SARS-CoV-2 Vaccines (PHASE3)
• Bacille Calmette-Guérin (BCG) Vaccine In Radiologically Isolated Syndrome (RIS) (PHASE2)
• Testing if BCG (Bacille Calmette-Guérin) Vaccination Can Induce Innate Immune Training in Adult People Above 50 Years of Age in Guinea-Bissau (PHASE4)
• Clinical Trial Evaluating the Effect of BCG Vaccination on the Incidence and Severity of SARS-CoV-2 Infections Among Healthcare Professionals During the COVID-19 Pandemic in Poland (PHASE3)

Primary sources

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