It is well accepted that vaccination is one of the most effective ways to prevent diseases. A vaccine helps the body’s immune system to recognize and fight pathogens like bacteria or viruses, which then keeps humans safe from the diseases they cause. Vaccines protect against a range of diseases, including Measles, Polio, Diphtheria, Tetanus, Meningitis, Influenza and Cancer. Viral vaccine manufacturing is a complex venture with the main steps being antigen production, purification and formulation. It takes between 8 to 36 months to produce, package and deliver vaccines to those who need them. This timeline includes testing each batch of vaccine at every step of its manufacturing process, and repeated quality control of batches by different authorities in the respective countries.
Challenges in Viral Vaccine Manufacturing: “The product is the process”
In the vaccine field, “the product is the process”. Regulatory authorities license not only a specific vaccine product, but also the manufacturing process by which that vaccine is produced, tested, and released for use. Minor changes in the production process may alter the final vaccine regarding purity, safety, or efficacy and thus require approval of health authorities in each country. Conventional viral vaccine manufacturing still uses chicken eggs and primary chicken cells for the production of viruses, although these are cumbersome technologies. Cell Culture Technology has become increasingly important in large scale manufacturing of vaccines due to increased productivity and low incidence of contamination versus traditional techniques using eggs. Today, a broad range of viruses can be generated in Vero and avian cell lines that are reliable and safe workhorses for industrial viral vaccine manufacturing.
Viral Vaccine Manufacturing to Control Pandemics:
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) has created a global public health crisis. Therefore, urgency in the development of vaccines is of vital importance to control the pandemic and prevent new viral outbreaks. Multiple vaccine types, such as DNA-, RNA-based formulations, subunits containing viral epitopes, adenovirus-based vectors and inactivated whole viruses are under development. In order to obtain viral stocks of SARS-CoV-2 virus strains, often Vero cells are used for plaque purification and initial passaging. Furthermore, Vero cells can be used for the production of SARS-CoV-2 virus vaccines. Purified inactivated (whole) viruses have been traditionally used for vaccine development and such vaccines have been found to be safe and effective for the prevention of diseases caused by viruses such as influenza or polio. The generation of a whole virus vaccine against COVID-19 using Vero cells is a promising approach to obtain a safe and effective vaccine. Such a product can be manufactured in very large commercial scale.