Understanding the Science Behind the COVID-19 Vaccine

You can hardly watch the news, look at social media, or talk to a friend without the COVID-19 vaccine being part of the conversation. People seem to have very strong views about the vaccine, both positively and negatively. Unfortunately, some of these strong opinions are founded in myths, untruths, and a basic misunderstanding of science.

Since this is the first vaccine developed using mRNA, there are a lot of technical and scientific terms being thrown about that can be difficult to understand without a background in science. This is probably the most technically complicated article I have written for this site yet. However, I think it is important for people to understand the science and the safety behind the approved COVID-19 vaccines. I decided to tackle the topic in hopes to calm fears and bolster confidence in the vaccine.

What is mRNA?

First, let’s start with some basic biology and explanation of terms. 

All cells contain genetic material. This allows the cells to replicate and carry out the functions necessary for life. The genetic material in cells is DNA and RNA:

DNA: short for deoxyribonucleic acid. It contains the genetic instructions and codes inside of cells that makes each species and individual unique. 

RNA: short for ribonucleic acid. Its principal role is to act as a messenger carrying instructions from DNA for the creation of proteins. Some viruses contain only RNA. There are three types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). For the sake of simplicity and because this is not a cellular biology lesson, we will only discuss mRNA here.  

mRNA:  this type of RNA acts as a temporary copy of information. It takes a portion of the genetic code to other parts of the cell for processing and the creation of a protein.  Essentially, the mRNA is telling the cells to build something inside themselves. 

How does mRNA work in vaccines?

In order to understand how an mRNA vaccine works, you must first have a general understanding of how traditional vaccines work.

The purpose of any vaccination is to teach the body’s immune system what a particular infectious disease looks like. This is done by presenting a particle specific to the virus or bacteria that causes the disease, or by using a weakened form of the cell itself.  This preemptive presentation of an infection disease makes it so that a defense against it may be started before the body ever encounters the disease. This preparation of the immune system allows for a rapid response and prevention of actual infection in case of exposure. Unfortunately, the actual creation of the vaccines, through growing cells and extracting the important pieces to present to the immune system, takes a significant amount of time. 

This is where mRNA vaccines have an advantage. Compared to growing cells and extracting the important pieces, large amounts of mRNA can be made quickly and less expensively in a laboratory. The idea of using mRNA in a vaccine started to be explored about 30 years ago – in other words, this is NOT new or rushed science. However, it has taken that much time to learn how to modify and use the mRNA in a safe way, in a way that still stimulated the immune system response, and in a way that still protected the mRNA in the body until it could enter the immune system cells.  The decades of research on the use of mRNA were able to be quickly put to use when the virus that caused COVID-19 was fully identified and a usable protein to stimulate the immune system was decided upon. 

In other words, the creation of mRNA vaccines did not happen in less than a year. It has been decades in the making. 

Another important point to note about how mRNA vaccines work is that they do not affect the DNA of the cell it enters. Remember, the job of mRNA is to be a “messenger” of information. It enters the cell and interacts with the parts of the cell that manufacture proteins. However the mRNA never enters the nucleus of the cell, which is where DNA lives. The mRNA does not interact with the DNA of the cell it enters, and therefore does not change or modify it. 

Is it safe?

There have been concerns raised about the speed of which the COVID-19 mRNA vaccines were developed, and that this may mean that they are potentially unsafe. That they were “rushed” and proper safety protocols may have been ignored. However, these vaccines were developed in the same way that previous vaccines have been, with a major advantage – extra funding and dedicated personnel. It takes a lot of time, money, and people to produce vaccinations, which is a major part of why they usually take so long to develop. However, with the COVID-19 vaccine, governments spent large sums of money dedicated to the one goal of producing a vaccine, which streamlined the process and made it more efficient. 

Clinical trials for vaccinations occur in three phases: 

• Phase one determines if the vaccine is generally safe. It is given to a small group of healthy people, who are then monitored for side effects. If the vaccine shows harmful effects, the testing does not go further. 
• Phase two involves a larger number of people who are split into two groups – the vaccine group and the placebo group. This phase allows researchers to look more in depth at the vaccine’s safety as well as if it generates immunity to the disease. 
• Phase three tests the vaccine on an even larger group of people (tens of thousands), in order to determine how effective the vaccine is, and what the best dosing regimen is. This phase of testing involves people of different ages and medical history/risk factors. Side effects and potential harmful effects are still monitored closely. 

At the end of Phase three trials, vaccines are submitted to the Food and Drug Administration (FDA) for approval. No vaccine is administered in the US without approval. Prior to approval, the FDA obtains a review of the vaccine from an outside panel of experts who include virologists, epidemiologists, biostatisticians, and microbiologists.  

Of note, the Pfizer COVID-19 vaccine was shown to be 95% effective after the second dose, while the Moderna vaccine was shown to be 94% effective after the second dose. Prior to the development of these vaccines, the goal set by the FDA for potential approval was 50%.

As of now, the COVID-19 vaccines from Pfizer and Moderna are only approved in children aged 16 years and up. There are ongoing trials to test the safety and efficacy of the vaccines in ages 12-16 years. It is unclear when or if these vaccines will be approved for ages below 12 years. 

The Future of mRNA uses

There is hope that since the technology and mechanism of mRNA vaccines can be so specific to a particular target, that it can be used to treat or prevent a range of other diseases. Researchers are looking at ways to develop mRNA vaccines for infections such as Zika virus and Influenza. mRNA can potentially present certain cancer proteins to cells. There is also research into providing treatment for autoimmune diseases such as Multiple Sclerosis, or genetic mutations such as in Cystic Fibrosis. 

Honestly, I think the potential for treatments for so many conditions is very exciting! Perhaps some good can come out of the COVID-19 pandemic in regards to a shift in how we treat conditions and diseases that were previously difficult to manage. 

Final thoughts

As a Pediatrician, I am frequently asked my thoughts on the safety of the COVID-19 vaccine, and whether I would recommend receiving it. Obviously, for my patients under age 16 years, the answer is currently “no,” because we don’t have the studies to prove that it is safe to give them. But for the rest of my patients – and family members, and friends, and coworkers – the answer is “yes!” Get the vaccine. Protect yourself and your family. Help us AND our children get back to normal life as quickly as we can. I am not recommending anything that I would not do myself… in fact, here’s a photo of myself after receiving the first dose last month.

Learn the facts. Ask the questions. Get the vaccine and encourage those you know to do so as well. 

Resources

https://www.childrenscolorado.org/conditions-and-advice/parenting/parenting-articles/covid-vaccine-updates/

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html

Why are mRNA vaccines so exciting?

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