What Exactly is in the COVID-19 Vaccine?

As the COVID-19 pandemic continues, scientists and biotech firms across the world are frantically trying to find a vaccine against COVID-19. So far, two major companies, Pfizer and BioNTech, have worked in conjunction to create a vaccine. This vaccine has been authorized for emergency use in the United States. Doses are being administered to healthcare workers on the frontline and is prescribed for anybody that is 16 years of age or older. Despite its authorization by the FDA, there are people who are still wary of getting vaccinated by a vaccine that hasn’t been tested for long-term side effects. This article will explain what the vaccine consists of and how it works in your body. 

The Pfizer-BioNTech vaccine consists mostly of mRNA and lipids. The use of mRNA is integral in the vaccine’s mechanism of action. Your body is essentially run by proteins: molecules which help in digestion, energy creation, and everyday activities are made up of proteins. Your body makes these proteins in cells by translating a strand of compounds that are called mRNA. You can think of mRNA like a recipe book; your body reads this recipe book and uses ingredients to create a protein. The vaccine contains a strand of mRNA that has been modified by scientists to contain the instructions for a “spike protein.” A spike protein is basically just a protein that is super unique to viral cells and located on the surface of COVID-19 viral cells. It is used by virus cells to infect normal cells, which is how COVID-19 can get into your body’s cells. 

Before going any further, we should examine exactly how our immune system works. Our immune system recognizes molecules that are not familiar to our body. After recognizing these molecules, the immune system naturally produces memory cells and antibodies whose function is to remember what that foreign molecule was. If the molecule is introduced into the body again, these memory cells and antibodies will alert other immune system cells, which will kill whatever compound has the foreign molecule. 

The vaccine also contains lipids. Lipids are organic compounds that are used by the body to make important molecules like fat and hormones. Many compounds in your body have charges on them. Lipids do not, which is why they are used so frequently in the medical field. Since lipids have no charge on them, they can easily pass through a cell’s outside barriers. The vaccine uses lipids in a capsule form; they encapsulate the mRNA in a lipid particle so that the mRNA can easily pass through the cell membrane. Once it passes through the cell membrane, it can code for the spike protein and induce the immune system. 

Putting these ideas together, here’s why the COVID-19 vaccine has mRNA and how it's supposed to work: first, the mRNA from the vaccine is delivered to our body’s cells through injection. Then, our cells will use the mRNA as a set of instructions to create the “spike protein” that is unique to COVID-19 viral cells. Once it does that, our body will realize that the spike protein is a foreign molecule and it will create memory cells and antibodies. There are two doses of the vaccine because the second time that the vaccine is administered, the body will recognize that the spike protein is present, and will create even more memory cells and antibodies. So, the vaccine harnesses our own body’s immune system to prevent infection by COVID-19.  

Thus, if we get exposed to COVID-19 after two doses of the vaccine, our immune system will recognize that the COVID-19 viral cells have the spike protein, and will immediately kill the viral cells, preventing infection. All of the components detailed above are not expected to produce an adverse reaction in our body. As we see people across the nation get vaccinated with Pfizer-BioNTech’s vaccine, we can only hope that there are no long term effects, and that our world will be back to normal soon. 

References:

https://www.fda.gov/media/144412/download

https://www.modernatx.com/mrna-technology/science-and-fundamentals-mrna-technology

https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf