The Vaccine Series: Vaccine Development

Vaccine development is a long and tedious process. According to the Centers for Disease Control and Prevention, multiple stages are involved and are summarized below: Explanatory Stage: Laboratory research is done and can last two to four years. Preclinical Stage: In vitro testing is done using enzymes, bacteria, and cells in test tube studies, followed by in vivo studies to determine Absorption, Distribution, Metabolism, Excretion, (Toxicity) – also referred to as ADME(T). These factors are important to consider when observing and analyzing the effects of the vaccine. If results produce a desirable response, the vaccine is sent to the Food and Drug Administration (FDA) under an Investigational New Drug application. This stage can last one to two years. Clinical Stage: If the FDA approves of the vaccine, testing its effectiveness and safety in humans can be done by the company that developed it. This stage can last several years and will be stopped if any of the phases provide unwanted results. Phase I involves a group of less than 100 healthy people who receive the trial vaccine. The focus here is on safety, ADME(T), safe dosage results, and the likelihood of side effects. Phase II involves the vaccine being distributed to a target group of less than 500 people. The purpose here is to observe the effectiveness of the vaccine and the possibility of short-term side effects. Phase III involves the distribution of the vaccine to a target group including thousands of people. The effectiveness of the vaccine, optimum dosage, long term side effects, and optimal route of administration of the vaccine are recorded and analyzed. Regulatory Review and Approval: If the clinical trials are successful, the company will propose a new drug application (NDA). If the FDA observes a higher benefit of the vaccine compared to the risk ratio, then the drug is accepted for clinical use. Despite this process taking several years, the FDA may fast track the vaccine for serious diseases, such as the novel coronavirus (COVID-19), before the clinical trials are completed. Production: Large quantities of the vaccine are produced and must meet the regulatory requirements. Quality Control: The newly developed vaccine may undergo post-market surveillance. In this process, further studies on the vaccine are conducted after it has been licensed and approved. There is a chance the drug could be taken off the market for various reasons such as additional health risks.

References

https://www.historyofvaccines.org/index.php/content/articles/vaccine-development-testing-and-regulation https://www.chop.edu/centers-programs/vaccine-education-center/making-vaccines/licensure-recommendations-and-requirements https://www.cdc.gov/vaccines/basics/test-approve.html https://www.cnbc.com/2020/08/30/fda-willing-to-fast-track-coronavirus-vaccine-before-phase-three-trials.html https://www.pfizer.com/news/hot-topics/how_are_vaccines_developed Dr. Len Luyt (2020). Chemistry 2223B. The Department of Chemistry at Western University

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