Vaccines are incredible. They protect us from diseases and strengthen our immune systems. They’ve also eliminated many deadly illnesses such as smallpox, and many only exist in a few countries. Such as Polio, which only exists in three different countries currently. They are an amazing medical accomplishment and have definitely increased life expectancy and survival rates. But how exactly do they work? How are they made, and how do we know that they are safe?
There are six stages in testing and regulating vaccines, and each of these stages has its own steps, so obviously, there are a lot of steps that go into making sure that they are safe.
The first stage is the exploratory step. This step is mainly just lab research and can often last anywhere from 2-4 years. Usually, scientists identify natural or synthetic antigens, which are substances that trigger an immune response in the body and lead to the production of antibodies.
The second step is the preclinical stage. This step uses cell-culture systems and animal testing to determine the saftey of the vaccine and its immunogenicity, which is the abilty to provoke a response from the immune system. During this stage they determine safe dosages and may change or adapt the vaccine. This phase usually lasts 1-2 years. After this step, a proposal is sent to the FDA, and once it is approved then they can move to the next step.
The third stage is clinical development is a three-phase step. The first phase is giving the vaccine to a small group of adults. Even if a vaccine is intended for children, the first phase only ever tests adults, later expanding to younger people. They monitor the reaction to the vaccine. In some cases, they give the pathogen to some to test the efficiency in controlled climates. If this phase shows promising then they move to the second phase which is a larger group of randomized people. Many times this includes those at risk of getting the disease. This tests reaction, immunogenicity, proposed doses, and the schedule of immunization. The final phase involves testing on thousands of people. This stage usually results in the finding of those rare reactions to vaccines. Efficiency is also tested during this phase. Many also have a fourth phase which is just observing the effects of the vaccine long after the approval of the vaccine.
The next stage is regulatory review and approval of the vaccine. The FDA regulates vaccines in the U.S. and they have a multi-step process for this. Once they approve of a vaccine, they continue to monitor the vaccine to ensure safety. That is done during the fifth and sixth stages, manufacturing and quality control.
The lengthy and thorough process of vaccine development show that they are safe for use, excluding the one-in-a-million rare side effects or those who have medical conditions that prevent them from getting vaccine, but it’s these people who require herd immunity, and while vaccines aren’t perfect they do help fight many deadly diseases and help protect those that are vulnerable.
All sources stem from CDC, Center for Disease Control, or are CDC approved.