Identification of a BCG Vaccination Scar

Clinical Significance and Implications of a BCG Scar

The Bacillus Calmette–Guérin (BCG) vaccine is widely used for tuberculosis (TB) prevention, particularly in regions with high TB prevalence. Following vaccination, individuals often develop a characteristic scar at the injection site. Identifying this scar has clinical relevance in determining vaccination history and assessing immune response.

Characteristics of a BCG Scar

• Appears as a small, raised lesion, typically on the upper left arm.
• Develops within weeks following vaccination.
• Persists as a permanent mark.

Clinical Implications

Recognition of a BCG scar assists in determining prior immunization status. This is crucial for epidemiological studies, vaccine efficacy assessments, and medical diagnoses. Additionally, certain immunological studies suggest that the presence of a BCG scar correlates with a stronger immune response against Mycobacterium tuberculosis.

Limitations and Considerations

Absence of a visible scar does not always indicate lack of immunization, as some individuals may have a subclinical response. Healthcare providers should rely on vaccination records along with clinical assessment.