How Quality Control Testing Helps Ensure Vaccine Safety

By Derek Jacobs, PhD, Bioproduction & ATMP at bioMérieux

Releasing a vaccine to the public where it can make a positive impact on public health and individual lives is a complex process. Quality control testing is critical at every stage, from initial development to full-scale production, to make sure vaccines are as safe as possible. There are different types of tests that serve different purposes, and there are also different types of tests that are needed depending on the type of vaccine being produced.

Mycoplasma Detection for Cell-Based Vaccine Production

Most vaccines are produced using cell-based processes, where a weakened or inactivated version of the pathogen is grown inside cells in a laboratory. An example of this is the flu vaccine, where the virus is grown inside of the cells of chicken eggs. Because production involves biological processes instead of synthetic processes, there are quality control steps that must be taken to prevent the cells (and therefore, the vaccine) from becoming infected with foreign pathogens.

Of particular concern are Mycoplasma, a type of bacteria that lack a cell wall, making them resistant to many types of antibiotics. To mitigate that threat, specific quality control procedures and tests have been developed to both prevent contamination and rapidly detect contamination if it occurs. The testing process helps companies discover contaminated products before they ever reach the public.

Quality Control for COVID-19 mRNA-Based Vaccines

The new COVID-19 mRNA-based vaccines, on the other hand, are produced completely differently, using synthetic processes instead of cell-based biological processes. Because of that, mycoplasma contamination is not a concern—there are no cells being used, so there is nothing for them to infect. However, there are other ways that vaccines, including the COVID-19 mRNA-based vaccines, can become contaminated.

Contamination can come from a variety of sources, including the air, water, equipment surfaces, and even personnel. This is why companies use strict quality control practices and maintain sterile production environments. Environmental monitoring helps companies keep tabs on the sterility of their production facilities—regular air, water, and surface testing can act as an “early warning” system that allows companies to detect contaminants before they reach products. Additionally, other types of diagnostics directly test the components of the vaccine and the end-product for contamination.

How Quality Control Measures for Vaccine Production are Developed

Companies do not come up with these quality control measures entirely on their own, and there is considerable regulatory oversight. The U.S. Food and Drug Administration (FDA) plays an integral role in the vaccine development and production process. From the beginning, FDA scientists review quality control documentation and data from company and institution scientists working on developing the vaccine, and then continue to do so at checkpoints throughout the process. The review process helps guide, define, and validate the appropriate quality control measures for the vaccine.

The team-based approach means that multiple scientists from each organization involved are able to review everything about the vaccine—from the preliminary research into vaccine candidates, all the way through clinical trials, and to full-scale production. Similar approaches are at work in other countries’ regulatory agencies as well, which means that every vaccine and production process is ultimately reviewed by multiple regulatory agencies.

Efforts to keep vaccines safe and effective are thorough and multi-pronged. Even though the COVID-19 vaccines proceeded through development, clinical trials, and production at an unprecedented pace, the sheer volume of resources involved—financial and scientific—was also unprecedented. Ultimately, everyone stands to benefit from successful vaccines, and that means that there is an enormous amount of pressure—and will—to get this right.


Opinions expressed in this article are not necessarily those of bioMérieux, Inc.

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