How do mRNA vaccines work?

Let’s talk about the new mRNA vaccines which may very well be employed to usher us out of the disaster that is known as 2020. If you find this useful, please don’t think twice about sharing. And I will say that this might be a complicated one to explain because there’s just so much that goes into the idea of an mRNA vaccine.

Back in the ’80s and ’90s, Head and Shoulders had a tagline in its commercials, “You never get a second chance to make a first impression.” I bring that up because I want to talk to you about mRNA vaccines before someone in your Facebook feed tells you the wrong thing about them.

You may have heard about a new kind of vaccine that “changes your DNA” and are understandably a little nervous about it. And it’s a fair thing to be uneasy about. People hear about DNA and genetics and it’s hard to understand because DNA is really, really complicated. When people start horsing around with anything DNA related, it starts invoking all manner of horror movies.

So let’s talk about this new type of vaccine–the mRNA vaccine. In order to understand how this works, you need to understand how mRNA works in your body and a refresher on how the other vaccines work as well. Here’s a link to the vaccine refresher that involves the flu shot. Take a real quick read.  I’ll wait…Refreshed? Good.

DNA: the Blueprints for Your Body

These new vaccines work on the same principles of training your immune system but go about it in a more complicated way.

If you don’t know, your DNA is the blueprints for everything that makes you, you. Your hair growth, when you heal a cut in your skin, your muscles rebuilding themselves, it’s all directed by your DNA. You have to make new blood cells every 120 days or so; your DNA is the blueprints for the building blocks to make more red blood cells. So what are the building blocks of all of this? The building blocks are the proteins that are made based on the instructions written in your DNA. The fancy way of saying this is that your DNA “codes” for these proteins. 

Essentially, the instructions in your DNA are taken to cellular machinery (the machinery is called “ribosomes”), the proteins are cranked out in a process called “translation” and you continue to exist. 

Everything you do comes down to proteins that your DNA “codes” for. Even what you’re looking at, right now, at this very moment.  When you see something, the image hits the retina in your eyes, which was there because your DNA coded for the proteins to make it when you were developing. The image gets converted into an electrical signal (again, via proteins that your DNA codes for), sent up your optic tract (put there because your DNA coded for proteins when you were in your mommy’s tummy), and sent to your brain where your brain uses a complicated series of proteins along with the infrastructure already in place (because of proteins) and you see these letters on the screen. More proteins in your brain help you convert the order of the letters into meaningful words.

The point is that the proteins that your DNA codes make all the stuff happen in your body including antibodies that make your immune system work. But not all cells can make every single protein. Your retina doesn’t make immune system antibodies because it doesn’t have the right machinery to crank out those specific proteins. The instructions are there in your DNA in the retina, but not the right ribosomal machinery. Your leukocyte b-cells (more commonly known as your white blood cells) on the other hand, well, antibodies are just their game. And, because your DNA has instructions to make everything, your b-cells can take the DNA instructions, crank out an antibody protein, and then add the special little cap on the end that binds to the bacteria or virus, and tags the invader for violent and horrible destruction.

mRNA Vaccines: The shortcut to making the right antibodies

Like I said, your DNA has instructions for literally every single thing your body can do. Taking that package of information and running it through a ribosome to make one protein is inefficient. Imagine if you were trying to build a building and all you were in charge of was painting the walls. But you had to flip through a 300,000-page manual to find the color of each wall you wanted to paint. That’s not efficient, right? Enter your mRNA. 

mRNA stands for messenger RNA. It’s like a copy of a few pages of the DNA. Again, the ribosomes can’t deal with the entire DNA library to make one protein so instead, your DNA unzips itself, makes a copy of the section that codes for the protein you need to be made, and that copy is called mRNA. It’s the mRNA that goes to the ribosome to make the protein so you can continue to exist. 

And so that’s how this new type of vaccine works.  The vaccine is a manufactured mRNA particle that finds it’s way to your ribosomes and starts cranking out the proteins you need.  Because I need pop-culture references for everything, it’s like that scene in The Matrix when Trinity needs to learn to fly a helicopter and she gets the instructions downloaded immediately.

Your immune system is saying, “Hey, let’s not get sick…I need to make the protein chains to make the antibodies to tag the coronavirus so if it shows up I can deal with it and you can keep binge-watching Netflix. Can you show me some coronavirus proteins so I can train what to look for?” And you’re answering with, “Nah,  I got something better. I got you the instructions to make the antibodies straight up.”

mRNA Vaccine AdvantageS

There are a lot of nice advantages to mRNA vaccines:

  1. People who are immunocompromised can take an mRNA vaccine. It’s not an infectious particle, not like the live attenuated vaccines and so it’s safe for people with a compromised immune system (go back and read the flu shot post if you need). People with compromised immune systems kinda need a good vaccine right now…
  2. It’s more effective to prevent illness. With the older vaccines, you still rely on your body’s b-cells to recognize the enemy and translate that into effective antibodies. That’s a pretty important step and sometimes your immune system, as darn near perfect as it is, makes a mistake. That mistake gets avoided with mRNA vaccines.
  3. We can make mRNA vaccines way more quickly. It is much easier to manufacture this type of vaccine on a faster scale, which is desperately needed right now.
  4. We can adjust the mRNA itself and “turn down” or “turn up” the immune response. If we see that people are having two or three days of chills and fever as a result of this vaccine and now everybody is claiming the vaccine gave them COVID-19 (it didn’t), we can play around with coding to increase or decrease the immunogenicity. And your immune response can be turned down or turned up. This is really, really cool. 
  5. Work on this might just cure cancer. mRNA vaccines could be the next evolution in cancer care.  See, your immune system stops you from getting cancer way more often than you want to know about.  When cells start to grow out of control, most of the time your immune system steps in and stops it. This is one of the reasons that immune suppression drugs for Crohn’s Disease or Psoriasis come with the “rare lymphomas have happened” warning on TV. This is also the reason Kaposi’s Sarcoma, a rare soft tissue cancer happened in AIDS patients. 

    This is also the reason that people get cancer more often as they get older. Your immune system starts to wear out – it’s called “immunosenescence.” When your immune system starts to get a little long in the tooth, sometimes it misses things. It misses cells that start to divide when they shouldn’t and turn into tumors. And you know what happens next.

    Now it’s possible that we might be able to someday take a cancer cell, analyze it, and then make an mRNA that codes for the antibody your body’s immune system can use to go tag and kill the cancer cells. It’s possible, and if we can do that, well, that’s huge.

An mRNA vaccine can’t change your DNA. It just can’t. Your DNA is your DNA from before you took your first breath, until even after your last. Your DNA became your DNA about twelve hours after conception (we probably don’t need to get into that). 

Your DNA is the instructions for everything about you. mRNA is simply another set of instructions to help your body make more proteins. The fact they made this work is amazing.

If you didn’t know, now you know. I hope that was a good first impression.

The expert family medicine providers at the Des Moines University Clinic are here to help you and your loved ones stay healthy year-round. If you think you or your family have been infected with COVID-19 and live in Polk County, call 2-1-1. If you have an upcoming appointment at the DMU Clinic please call in advance. More information is available on DMU’s coronavirus response website.

Disclaimer: This content is created for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health care provider with any questions you may have regarding a medical condition.

Jonathan Crosbie, D.O.

Dr. Crosbie is an assistant professor in the Departments of Osteopathic Medicine and Family and Internal Medicine at Des Moines University. In addition to his academic responsibilities and providing excellent patient care in the Family Medicine Clinic he is an avid activist for preventative medicine and living a healthy lifestyle. In his spare time he enjoys motorcycling, woodworking, movies and sports, and spending time with his family.

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