Producing a new vaccine (or any other drug) requires a lot of effort and people. According to the “Centers for Disease Control and Prevention” (CDC) [1], there are six stages for vaccine development. All six stages involve thousands of people, from researchers in academia and health professionals, to government agencies and manufacturers in the private industry.
The full process begins with a hypothesis by an investigator in a research lab at one of the many reputable research institutions around the world. A hypothesis is a prediction that is backed up by years of scientific literature that suggest or support a useful mechanism for disease prevention. During the exploratory stage, the principal investigator of the laboratory will apply for funding from the government or other agencies to test this hypothesis. This funding will finance the expensive equipment and labour required to perform experiments. Investigators work together to find new ways of prevention and treatment for a particular disease.
In the case of vaccines, this process will help identify natural or synthetic antigens*. Antigens are the elements of the virus that will trigger an immune response. In this stage, collaboration between scientists is essential. Researchers review published works and make suggestions and comments on the credibility of the research methods. Often, experiments are repeated multiple times in multiple labs and approached from many angles to increase accuracy. This exchange of ideas and results helps maintain the integrity of the scientific process and has proven effective at generating reliable results.
Once the scientific community has generally agreed on effective results, other researchers – usually in the private industry – take over and use cell cultures and animal models to determine the efficacy of the candidate vaccine [2]. This is known as the preclinical stage. This is a fundamental process to test whether the vaccine will produce immunity, or if it is harmful to the body. Only vaccine candidates that demonstrate reliable immune response and minimal adverse effects in the preclinical stage can move on for further investigation.
The clinical trials are three phases that differ in the amount and health condition of the volunteers [3]. During phase I, less than 100 healthy volunteers take the vaccine to determine whether it is safe. Phase II includes hundreds of individuals that may belong to groups with similar characteristics to the target population. This phase evaluates the vaccine dosage, preliminary efficacy, and side effects. Lastly, Phase III is a larger trial, involving thousands to tens of thousands of people. The goal is to assess the vaccine safety in the general population.
After a successful Phase III trial, the health authorities of each country, for example Health Canada, evaluate the safety and efficacy to assess potential benefits and risks of the vaccine [4]. Once the vaccine is approved, it can be manufactured and distributed. However, these authorities continue to oversee its production to ensure its safety, and it can reconsider its decision if there are new side effects or, if the vaccine does not produce the desired effect.
As you can see, the process of making a vaccine is long and has many phases to ensure its safety. The question now is, how has the COVID-19 vaccine been produced in only a year? Does this make it unsafe? No! The COVID-19 vaccine has followed the same stages and tests as any other vaccine. The only difference is that most COVID-19 vaccines have done this process a lot faster just by overlapping the different phases and starting manufacturing early. Also, there has been a lot of funding and collaborations worldwide, which has reduced the exploratory phase.
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*Antigen - a molecule or substance that is considered foreign to the organism. It can be a toxin, a small part of a microorganism in cases of infection or it can even be a small part of our own body in cases of autoimmune diseases. The antigens stimulate an immune response and the production of antibodies.
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Written by: María
Edited by: Adrian and Natasha
BioDecoded is a volunteer group committed to sharing accurate scientific information. We cannot offer any specific health advice. If you have any doubts about getting vaccinated due to previous health conditions, please speak with your healthcare professional or family physician. Your doctor can revise your medical history and advise you on the best path to follow. If you have any questions about this topic, please comment or send them to our email.
References:
National Center for Immunization and Respiratory Diseases. Vaccine Testing and Approval Process | CDC. (2014). Available at: https://www.cdc.gov/vaccines/basics/test-approve.html. (Accessed: 13th April 2021)
Milken Institute School of Public Health, T. G. W. U. Producing Prevention: The Complex Development of Vaccines – Resources. (2019). Available at: https://onlinepublichealth.gwu.edu/resources/producing-prevention-the-complex-development-of-vaccines/. (Accessed: 13th April 2021)
PBL Pacific BioLabs. Stages of Drug Development – Pacific BioLabs. Available at: https://pacificbiolabs.com/stages-of-drug-development#ind. (Accessed: 13th April 2021)
How Drugs are Reviewed in Canada – Canada.ca. 2015 Available at: https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/fact-sheets/drugs-reviewed-canada.html. (Accessed: 13th April 2021)
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