Vaccine vial dose with needle syringe, medical concept vaccination in laboratory background
What should the public know about vaccine development as a whole? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world.
Vaccine development is a laborious and costly endeavor. Typically, a vaccine takes 10 years and $1 billion USD to be used in the general population. Benefit versus Risk is the key to vaccine development. The vaccine must offer a benefit that outweighs the risks. Fortunately, the work of the past 100 years, more so the past three decades, has helped to decrease the time needed to develop a candidate and test it in clinical trials. We are close to about a 3-month time frame to develop a vaccine candidate and begin safety testing in humans. New approaches allow past knowledge and new information (virus sequence and proteins) to be placed in “platform” approaches that now exist. These platforms are proven methods to express the new virus protein in humans to allow our bodies to build immunity to the new pathogen. When a new pathogen is found, sequences allow us to design new proteins to express in the platform vaccine. Cut and paste approach. However, it remains a vaccine candidate until testing is done to show it is safe. Safety is always the priority, so studies are done to make sure it doesn’t hurt the patient. This is done with in vitro (test tube) and in vivo (animal) testing and then small Phase I human safety clinical trials. In Phase 1, healthy people (ideally who can benefit from the vaccine) are given the vaccine at increasing doses to see if there are any “adverse events”, even simple pain at the injection site! This has started for some of the vaccines. Next, the immune response is monitored in those first people to see how they respond. This can be weeks, to months later. We often look a year and years out to see how long their response to vaccine is to determine if the vaccine is “durable”, meaning it lasts over time. This is why we get booster shots because, over time, some vaccines need additional shots to keep us protected. In Phase 2, the number of people is increased and we look for “efficacy” and safety. Efficacy is the benefit from the vaccine or protection from infection. Often, we find that some people are protected, others receive partial protection and have limited disease compared to those that have no vaccine. Given genetic differences some people don’t respond at all. Thus, those individuals derive no benefit from the vaccine. Next we expand to further people to demonstrate efficacy and safety in larger groups of people. In all steps, close attention is paid to adverse events, short term, and long term. Typically this takes years, but in pandemics this is done rapidly and can be done in about 12-18 months.
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