BCG Vaccine

Preparation of BCG Vaccine:

1. Production:

   • BCG (Bacillus Calmette-Guérin) vaccine is prepared from a live, attenuated strain of Mycobacterium bovis.
   • The bacteria are cultured in a medium containing specific nutrients (e.g., glycerol, potato starch, and asparagine).
   • After several weeks of incubation, the bacterial culture is harvested and tested to ensure the proper growth and attenuation.

2. Lyophilization (Freeze-Drying):

• The bacterial suspension is concentrated and then freeze-dried (lyophilized) to produce a powder form of the vaccine.
• This process ensures the stability of the vaccine over long periods and makes it easier for storage and transportation.

Standardization of BCG Vaccine:

1. Potency Testing:

   • The potency of the BCG vaccine is standardized by testing its ability to induce a specific immune response.
   • This is done by inoculating animals (usually guinea pigs) and measuring the size of the local reaction or observing the development of immunity.

2. Viability:

   • The vaccine must contain a minimum number of live bacilli per dose (usually between 0.1 to 0.2 mg of dry weight and contains approximately 2-8 million colony-forming units).
   • Viability tests are conducted to ensure that the live bacteria are effective and potent enough for vaccination.

Labeling of BCG Vaccine:

1. Contents:

   • The label must indicate the strain of Mycobacterium bovis used (e.g., Danish 1331 strain) and the number of viable organisms per dose.

2. Expiry Date:

   • The label should include the expiry date after which the vaccine should not be used.

3. Instructions for Use:

   • The label should provide clear instructions for the reconstitution of the vaccine, the method of administration (usually intradermal), and dosage (commonly 0.05 mL in infants and 0.1 mL in adults).

4. Storage Conditions:

   • Clear instructions for storage, typically indicating that the vaccine should be kept at 2°C to 8°C, protected from light, and not frozen.

5. Warnings:

   • The label should contain any necessary warnings about contraindications, potential side effects, and instructions to monitor for allergic reactions.

Storage of BCG Vaccine:

1. Temperature:

   • The vaccine should be stored in a refrigerator at 2°C to 8°C. It is important to avoid freezing the vaccine as this may reduce its potency.

2. Light Protection:

   • BCG vaccine should be protected from direct light, which can degrade the potency of the live bacteria.

3. Reconstitution:

   • Once reconstituted with a diluent (usually saline), the vaccine must be used within 6 hours. After this period, it should be discarded as the viability of the bacteria decreases.

4. Monitoring:

• The vaccine vials should be inspected regularly to ensure they are within the expiry date, and any vials with visible signs of damage or contamination should be discarded.