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Active ingredients:


Meningococcal B vaccine


Active ingredients:

Recombinant proteins and Outer Membrane Vesicles (OMVs)

Bexsero is a recombinant protein vaccine: the information for how to make specific proteins is inserted into the genome of Escherichia coli (E. coli), which is a species of bacteria that naturally inhabit the intestines and are generally harmless. The E. coli produce the proteins, which are used as the active ingredients in the vaccine. Because these are proteins, not whole bacteria, you cannot get meningitis B from the vaccine. 

The other active ingredient is outer membrane vesicles (OMVs), which refers to a piece of the cell membrane from the bacterium that split off from the rest of the cell. These vesicles are naturally produced by bacteria, but are not infectious because they contain no genetic material and cannot replicate. OMVs contain surface antigens that the immune system can use to produce antibodies.

Inactive ingredients:
Ingredients based on a 0.5mL dose

Adjuvants: strengthen the immune response to the vaccine

Salts: help maintain the stability and pH of the vaccine

Carbohydrates: normally used as stabilizers in vaccines

Antibiotics: used to prevent contamination during the manufacturing process

Other Stabilizers:

Relevant Terms

Relevant Terms

  • Adjuvant: a compound added to some vaccines to strengthen the immune response

  • Antibiotics: substances that kill bacteria or prevent them from dividing. Antibiotics are used in some vaccines to prevent contamination during the manufacturing process

  • Antibody: a protein made by the immune system in response to a foreign particle (antigen). These proteins circulate in the blood and help defend the body against the substance.  

  • Antigen: This is any substance that triggers the immune system to create antibodies. For example, allergens such as pollen are antigens.

  • Carbohydrates: This is another word for sugars. 

  • Genome: all of the genetic information in a cell.

  • Molarity: a measure of the concentration of a substance. It is defined as the moles of a substance in a liter of water. A mole is a standard unit in chemistry defined as 6.022*1023 molecules of a substance.

  • pH: a measure of how acidic or basic a solution is. The scale ranges from 0 (very acidic) to 14 (very basic). A pH of 7 is neutral.


Last updated: Feb. 23, 2023

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