It takes about 12 to 18 months before manufacturers can be licensed to provide the vaccine to 50% of the world’s population. For the remaining 50 per cent, including a significant percentage of children under 5 years of age, an additional 48 months are required.
This is due to the extreme complexity of manufacturing and the time spent on controls.
Principle of the vaccine :
Steps for the manufacture of the vaccine
We mainly group together viruses that need to keep their properties constant in order to produce quality vaccines.
Demanding quality controls are necessary
We’re looking for a large quantity of germs that are identical in every way. It is necessary to follow very strict rules of asepsis and under strictly constant conditions (temperature, culture medium…). Demanding quality controls are essential.
To do this, the germs are introduced into a living organism (an animal, egg yolks, etc.) to help it develop. This is the process of inoculation or seeding.
Antigens are molecules specifically recognized by the immune system and capable of inducing the production of antibodies.
The quality depends on the number of antibodies capable of neutralizing the antigen (antigenic valences) and the number of diseases against which a vaccine is supposed to protect us (vaccine valence).
Live attenuated vaccines do not need to be inactivated.
Inactivated vaccines contain infectious agents that have been killed by a chemical or by heat. They remain capable of eliciting a response from the immune system.
Extensive checks are carried out to ensure that no bacteria are present that do not conform to the vaccine.
Adjuvants are added to vaccines to increase their effectiveness.
Stabilizing agents are used to maintain the quality of the vaccine during storage.
Preservatives are substances used to prevent the growth of bacteria in vaccines.
Mixing the necessary “ingredients” and freeze-drying.
Animal experiments are carried out.
Immunogenicity is then studied in a small number of healthy volunteers.
The candidate vaccine is administered in different doses to a target population that is monitored for injection tolerance, immunological efficacy and clinical effectiveness.
Finally, a large-scale, real-world efficacy trial is conducted.
70% of vaccine manufacturing time is spent on controls.