[Should the BCG vaccine still be recommended?]

Area of Science:

• Immunology
• Vaccinology
• Infectious Diseases

Context:

• Tuberculosis (TB) remains a significant global health concern, particularly in its severe extrapulmonary forms affecting young children.
• The Bacillus Calmette-Guérin (BCG) vaccine is a primary tool for preventing childhood tuberculosis.
• Limited duration of BCG-induced immunity and potential adverse effects necessitate a nuanced approach to its global application.

Purpose:

• To evaluate the efficacy and limitations of the BCG vaccine in tuberculosis prevention.
• To assess the durability of BCG-induced immunity in different age groups and geographical contexts.
• To inform vaccination guidelines based on disease prevalence and risk-benefit analysis.

Summary:

• BCG vaccine effectively protects young children against severe extrapulmonary tuberculosis.
• Immunity wanes in adults, and revaccination with BCG does not restore protection.
• Rare but severe adverse events, such as disseminated vaccinal infections, are a concern.

Impact:

• BCG vaccination is recommended for children in high-prevalence tuberculosis countries and those traveling to such regions.
• In low-incidence areas like Western Europe, the risks associated with BCG may outweigh the benefits, leading to restricted use.
• Further research into alternative or booster strategies for tuberculosis prevention in adults is warranted.