Updated: Aug 29
Author: Jefferson Lin
Editors: Peggy Yang, Kyra Wang, and Shirley Chen
Artist: Acey Li
Have you ever wondered how vaccines work to protect us from dangerous diseases? Having the capacity to halt the spread of illnesses that once caused major epidemics, vaccines have become a vital tool in modern medicine. But how exactly do they work, and how did they become such an important part of public health? Are there various types of vaccines? Why do we need to get vaccinated every year? In this article, we'll look at the interesting science behind vaccines, their purposes, and how they've transformed modern medicine. From looking into the history of modern vaccines to understanding the different types of vaccines to finally having a general understanding of the necessity of vaccines.
Though it was believed that people throughout history—going back as early as 200 BC—have been attempting to create vaccines or methods to prevent illness, the earliest recorded successful vaccine was created by Edward Jenner in 1796. He did this by exposing a child to cowpox, which led the child to be sick for a couple of days before they were healthy again. When they got smallpox, they managed to fight it off and remained decently healthy even though smallpox had a mortality rate of over 80% when children were exposed to it at that time. To honor this discovery, the term vaccine is derived from the Latin word for cow and vacca, which was used to describe the cure for diseases. After a couple of decades, in 1872, a brilliant chemist named Louis Pasteur created the first lab-produced vaccine to counteract fowl cholera in chickens. A few years later, he created a vaccine that prevented rabies involved in post-exposure vaccination.
With the rise of the 1900s, vaccines have become very popular and crucial for human survival. Numerous vaccines have been developed to counteract deadly diseases such as influenza, polio, hepatitis, pneumonia, etc. While going fully in-depth into the history of vaccines is truly fascinating, the gist of the history of vaccines is that these brilliant scientists have created, tested, and experimented on these viruses to find solutions that would best help the human body to destroy or fight off the virus.
Now let's go into the science behind how they work. Before we talk about vaccines, we’ll talk about what your body does for you. There are countless bacteria in your body and the outside world. Some may be harmless and some may even help your body. Others, such as viruses, mostly seem to harm your body. When viruses enter your body, they will multiply and attack your systems. However, our body's defense mechanism is complex, with the immune system being able to counteract some of these attacks. The immune system sends out white blood cells to fight off the virus by either consuming the virus, producing antibodies to fight off the infection, or wiping out infectious or newly developed cancerous cells. However, some diseases are not easy to fight off. Think of your immune system as a cookbook. When empty, it knows its default attacks and defenses against viruses. Most are easy to record and fought off by the immune system. However, some of the not-so-easily written down need the addition of vaccines into the mix. The immune system will be able to study the similar substance (sometimes smaller, less threatening versions of the actual virus) and write it down in the cookbook to obtain more knowledge on how to fight specific viruses.
There are different types of vaccines that doctors use to fight off certain illnesses. Some of the more popular vaccines are live, attenuated vaccines, non-live vaccines, and subunit and conjugate vaccines.
Live, attenuated vaccines are vaccines that send the same, but weakened pathogen to the body that replicates in the body and triggers an immune response. The immune system then creates antibodies against the weakened pathogen, protecting against future infections.
Similar to live, attenuated vaccines, non-live vaccines will send a killed or inactivated version of the pathogen so that it cannot cause disease. These vaccines typically contain parts of the pathogen, such as proteins or sugars, rather than the entire organism. The immune system will treat this as a foreign substance in the body and will attend to it. Because they send a dead version of the virus, they are considered safe because there will be no side effects. For example, a booster is often required when taking a non-live vaccine to maintain immunity.
A subunit and conjugate vaccine works by sending only a specific part or component/s of the pathogen that is capable of triggering an immune response. The subunit used in the vaccine can be a protein, a fragment of a protein, or a sugar molecule from the pathogen.
All in all, vaccines are wonderful inventions created by brilliant scientists to help the immune system to stop diseases. There are various types of vaccines and all have their benefits and side effects, but they definitely help add more recipes into the immune system “cookbook” to ensure your immune system fights off the same virus that tries to harm the body.
Centers for Disease Control and Prevention. (2023, May 24). Explaining how vaccines work9.
Centers for Disease Control and Prevention.
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