Whole cell vaccination for meningococcus: Lessons from an idea whose time has gone

Area of Science:

• Vaccinology
• Microbiology
• Immunology

Background:

• Endotoxin is typically viewed as a vaccine contaminant causing adverse events.
• Novel vaccine candidates, especially for Neisseria meningitidis using native outer membrane vesicles (NOMV), incorporate endotoxin as an antigen or adjuvant.
• Historical use of endotoxin-containing vaccines provides context for current developments.

Observation:

• From 1907-1939, approximately 400,000 individuals received whole-cell meningococcal vaccines.
• Adverse event reports from this period were reviewed to establish a safety baseline.
• The majority of studies indicated good tolerability for these whole-cell vaccines.

Findings:

• Whole-cell meningococcal vaccination adverse event profiles were comparable to other Gram-negative bacterial vaccines.
• The historical vaccines were generally well-tolerated.
• Insufficient data exists regarding the protective duration induced by these early whole-cell meningococcal vaccines.

Implications:

• Findings provide a historical safety benchmark for evaluating new meningococcal NOMV vaccines.
• Understanding historical endotoxin use informs the safety assessment of current endotoxin-containing vaccine candidates.
• Further research is needed to determine the long-term efficacy of historical meningococcal vaccines.