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Stabilisation of BCG vaccines
M Gheorghiu1, M Lagranderie, A M Balazuc
1BCG Laboratory, Institut Pasteur, Paris, France.
Developments in Biological Standardization
|January 1, 1996
Summary
Optimizing Bacillus Calmette-Guérin (BCG) vaccine stability is crucial for tuberculosis prevention. Freezing offers superior long-term viability for research, while freeze-drying provides adequate stability for mass vaccination campaigns.
Area of Science:
- Immunology
- Vaccinology
- Microbiology
Background:
- Bacillus Calmette-Guérin (BCG) vaccine efficacy relies on bacillary survival, multiplication, and persistence within host organs.
- Vaccine viability and stabilization during storage are critical for optimal immunogenicity.
- Conventional BCG vaccine manufacturing methods, such as ball milling, significantly reduce bacillary viability.
Purpose of the Study:
- To investigate factors influencing BCG vaccine viability and explore stabilization methods.
- To compare the efficacy of freezing and freeze-drying techniques for preserving BCG.
- To determine optimal storage conditions for maintaining BCG viability.
Main Methods:
- Utilized dispersed deep-grow BCG, offering a live suspension before stabilization.
- Employed two primary stabilization methods: freezing and freeze-drying.
- Assessed viability after resuspending BCG in cryoprotective solutions and storing at various low temperatures.
Main Results:
- Complete BCG survival was achieved by freezing in glycerol solutions and storing at -70°C for extended periods.
- Freeze-drying resulted in over 50% loss of live bacilli, but preserved remaining bacilli at -30°C for 20 years or 4°C for 1 year.
- Freeze-dried BCG demonstrated resistance to 37°C for one month, though a majority of bacilli remained non-viable.
Conclusions:
- Both freezing and freeze-drying of young, dispersed-grown BCG bacilli yield the best viability.
- Freezing is ideal for research and cancer immunotherapy; freeze-drying is suitable for tuberculosis prevention vaccination campaigns.
- Further improvements in BCG stabilization techniques are necessary.