Vaccines are biological products that elicit a protective immune response. Details of the manufacturing processes are varied depending on the particular characteristics of each vaccine.
There are basically 3 classical types of vaccines against viral and bacterial pathogens: Live-attenuated, Killed (non-live), and Subunit vaccines. Since 2020 also genetic vaccines are licensed (DNA/mRNA/Vector) vaccines.
The basic production process for the 3 classical vaccine types includes 5 phases: expression, harvest, inactivation, purification, formulation.
Bacterial expression is performed in fermenters. Viral vaccines are produced in animal cell culture or embryonated chicken eggs.
Subunit vaccines routinely require the most purification to separate the product from other contaminants.
Challenges for the production of bacterial vaccines include testing to ensure the safety and efficacy of the product. Live attenuated vaccines need to be tested to ensure the vaccine strains are still safe and effective.
Viral vaccines require testing to ensure foreign infectious agents are not introduced during processing.