Adverse reactions to BCG

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• BCG vaccine substrains used in the Czech Republic post-WWII included Copenhagen, Prague BCG 725, Moscow BCG, and Behring BCG.
• Introduction of Moscow BCG (1981-1993) correlated with increased local/regional lymph node adverse reactions and bone/joint involvement in infants.
• Molecular genetics can identify these BCG substrains.

Purpose of the Study:

• To analyze post-vaccination adverse reactions associated with Moscow BCG (1981-1993).
• To evaluate the impact of reduced vaccination dosage on adverse reaction frequency.

Main Methods:

• Retrospective analysis of adverse reaction data for Moscow BCG vaccine use (1981-1993).
• Comparison of adverse event rates between full (0.05 mg) and reduced (0.025 mg) BCG vaccination doses.
• Data collection on local, regional lymph node, and bone/joint complications.

Main Results:

• Full dose Moscow BCG: 0.08% local, 0.01% regional lymph node reactions; 6.5% required chemotherapy, 24% surgery.
• Reduced dose Moscow BCG: 0.1% local, 0.01% regional lymph node reactions; 3.1% required chemotherapy, 4.8% surgery.
• Bone and joint involvements occurred in 3.7 per 10^5 infants vaccinated with the full dose.

Conclusions:

• Reduced dosage of Moscow BCG vaccine led to a significant decrease in regional lymph node complications and subsequent medical interventions.
• Despite a slight increase in local reactions, the lower dose demonstrated a favorable safety profile regarding severe adverse events.
• The findings highlight the importance of vaccine dosage optimization for BCG to minimize adverse reactions while maintaining efficacy.