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mRNA 101

By now, you've heard all about mRNA vaccines. But what is mRNA, how does it work in our bodies, and how is it used to make vaccines?

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To understand mRNA, let's talk about DNA

DNA (short for Deoxyribonucleic acid) is found in every cell nucleus in our bodies. Our DNA provides the genetic code that our bodies need to create the proteins that we use everyday to function.

Think of DNA like a recipe that the body follows on how to make you the individual that you are.1

What is mRNA?

If DNA is the recipe the body follows, mRNA (short for messenger ribonucleic acid) is the messenger who delivers the recipe instructions to the chef. Your DNA provides a template for the creation of mRNA, which is made naturally in your body. Through a process called transcription, mRNA is generated by copying the template provided by your DNA.2

How does mRNA work in our bodies?

The mRNA that is created is essentially a list of instructions that are used by cells to create all of the proteins in our body. This process of creating protein from the mRNA instructions is called translation.2

Proteins play many critical roles in the human body.

Proteins play many critical roles in the human body. They are involved in almost every biological process, from DNA replication to helping us fight off disease and using our muscles to move. In fact, scientists believe that humans have as little as 20,000 to as many as several million proteins needed for our bodies to function properly, and each one was made based on the instructions carried by mRNA.3

To understand mRNA, let's talk about DNA

DNA (short for Deoxyribonucleic acid) is found in every cell nucleus in our bodies. Our DNA provides the genetic code that our bodies need to create the proteins that we use everyday to function.

Think of DNA like a recipe that the body follows on how to make you the individual that you are.1

What is mRNA?

If DNA is the recipe the body follows, mRNA (short for messenger ribonucleic acid) is the messenger who delivers the recipe instructions to the chef. Your DNA provides a template for the creation of mRNA, which is made naturally in your body. Through a process called transcription, mRNA is generated by copying the template provided by your DNA.2

How does mRNA work in our bodies?

The mRNA that is created is essentially a list of instructions that are used by cells to create all of the proteins in our body. This process of creating protein from the mRNA instructions is called translation.2

Proteins play many critical roles in the human body.

Proteins play many critical roles in the human body. They are involved in almost every biological process, from DNA replication to helping us fight off disease and using our muscles to move. In fact, scientists believe that humans have as little as 20,000 to as many as several million proteins needed for our bodies to function properly, and each one was made based on the instructions carried by mRNA.3

How do mRNA vaccines work?

mRNA vaccines work like other vaccines, which help prepare our immune system to fight off foreign invaders like bacteria and/or viruses. Vaccines do this by teaching our immune system what a virus looks like so that it can be targeted and destroyed.4

What is different about mRNA vaccines is that they work by introducing a piece of information, or a blueprint for your body: the mRNA teaches our body how to respond. The mRNA in a vaccine behaves like any other mRNA made by your body. When the mRNA vaccine enters our body's cells (but not its nucleus), the mRNA provides the instructions to create a protein called an antigen.5 An antigen is a protein that our immune system uses to recognize if something is foreign like a virus or bacteria.6

Did you know?
mRNA can never travel into the cell nucleus and alter your DNA. DNA resides in the nucleus where it is protected from change.

The antigen then triggers a natural response when it comes in contact with our immune system. This natural response leads to the creation of proteins specific to the virus, known as antibodies.5

Antibodies help the body fight infections by identifying and attaching to a virus. They are telling the immune system that the virus should be destroyed.5

Did you know?
The mRNA and the tiny fatty droplets it is wrapped in (called lipid nanoparticles, or LNP) introduced into the body from the vaccine naturally degrades and leaves your body within 2 days.7,8

The mRNA introduced into the body from the vaccine naturally degrades within 2 days. Antibodies that are naturally created using your body’s machinery, however, stay in our body after vaccination to help our immune system respond quickly should our bodies be exposed to the virus in the future. This allows our bodies to ‘tag and destroy’ the virus before it can make you sick.

One important aspect of mRNA vaccination, compared to other vaccines, is that your body is never exposed to the virus. Other traditional forms of vaccines are created by introducing a harmless part of the bacteria or virus into the body to develop antibodies against a particular disease. mRNA vaccines work differently by merely introducing a set of instructions for your body to develop its own immunity towards the virus.

A brief history of mRNA Vaccines

1960s
mRNA was first discovered in the human body. Scientists started exploring whether vaccines could be made using mRNA.8, 9
Scientists began to wonder: instead of injecting a weakened form of a virus, what if they could deliver mRNA to the body to provide instructions for the cell and make this little piece of the virus? However, to be effective, mRNA has to enter the cells in our body so that it can deliver its message.11

Initially, there was a challenge because when mRNA is administered into the body, it is particularly unstable and breaks down into harmless pieces that get quickly recycled by our bodies before it can make its way into the cell.
1970s
1990s
The solution to this problem came later with advances in nanotechnology. To transport the mRNA effectively, mRNA is wrapped in tiny fatty droplets called lipid nanoparticles. These fatty bubbles are transported through the body and allow the mRNA to enter the cell so that they can deliver their RNA message to create proteins.11

Now with a method of delivering mRNA into the body, several mRNA vaccines and medicines have been developed and studied over the past 30 years.
The first mRNA vaccine reaches human clinical trials for rabies. This vaccine showed only a weak immune system response, but what it did show was that the mRNA vaccine technology was safe for humans.11
2013
2020
Thanks to decades of research, mRNA vaccine technology was ready when the world was faced with the COVID-19 pandemic. The last hurdle to overcome was that mRNA vaccines are quite difficult to transport and needed to be stored at low temperatures. The threat to global health posed by COVID-19 ensured that governments and industry came together to mitigate these logistical challenges and bring the first ever fully approved mRNA vaccines to market.

The success of these mRNA vaccines cannot be overstated and without them the impact of the pandemic may have been far greater. The success of mRNA vaccines has opened the door for the potential of future mRNA-based medicines that could transform the world of medicine.

mRNA Vaccines are a Public Health Breakthrough

mRNA vaccines be developed faster than traditional vaccine technology

mRNA medicine has the potential to revolutionize modern medicine

Vaccine Monitoring and Safety

In contrast to traditional vaccine manufacturing, mRNA vaccines do not need to grow large quantities of the virus or bacteria that causes the disease and then weakening or inactivating it so that it can be used in a vaccine. This traditional process of vaccine manufacturing is time-consuming and leads to longer development time.

Instead, the mRNA sequence (instructions) that is needed to create the protein (which helps your body develop an immune response) is developed on a computer.12 From there, scientists use this as a blueprint to physically create the mRNA sequence in the laboratory. This also means that mRNA vaccines are a much more adaptable than traditional vaccines and can be easily modified to target new variants of a virus (for example, the Omicron variant of COVID-19).
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This was one of the reasons why scientists were able to develop an mRNA vaccine against COVID-19 so quickly. In fact, the two main COVID-19 mRNA vaccines began clinical trials less than 2 months after their development in the laboratory had begun. This, along with the unprecedented collaboration among governments, regulatory bodies, and vaccine manufacturers enabled the world to get the COVID-19 vaccine in record time.

Did you know?
Even though mRNA vaccines have only been approved for use since 2020, mRNA technology has been developed over several decades, beginning in the 1960s.

One of the things that make mRNA vaccines so exciting & innovative is not only their ability to combat contagious diseases but also their potential to treat cancers and rare diseases.

mRNA technology could be used to treat cancer in a similar way as it does a virus by making the body create a protein that can help the immune system recognize and destroy cancer cells. The mRNA gives instructions to the body to make a protein on the surface of the cancer cell. This helps the immune system recognize the cancer and destroy it.

mRNA technology also has the potential to treat rare diseases where the body lacks a certain protein. mRNA medicines can give instructions to the body to create the missing protein, which can help the body work properly and improve the person's health.

Just because mRNA vaccines can be developed quickly does not mean that they do not undergo the same strict clinical trials that all other vaccines do. Health Canada evaluates every vaccine before approving them to make sure that they are safe and effective at preventing the disease in question. Even after a vaccine is approved, Health Canada and the Public Health Agency of Canada continuously monitor the safety of the vaccines throughout their lifetime.

If you have questions about the safety or side effects of a vaccine, ask your family doctor or a healthcare provider for more information. If you want to learn more about vaccine safety, you can also visit the Health Canada's website.

Test your mRNA knowledge

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mRNA technology is only useful for developing vaccines and cannot be used for other medical applications.

True
False

The correct answer is: 

mRNA technology has the potential to treat rare diseases and cancer, in fact there are mRNA medications right now undergoing clinical trials for that purpose.

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mRNA vaccines work by introducing mRNA into the body to instruct cells to make a protein found on the surface of a virus.

True
False

The correct answer is: 

mRNA introduced by a vaccine uses the cell machinery in our bodies to create a protein found on the surface of a virus to create a natural immune response.

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mRNA technology has been around for decades and is a well-established field.

True
False

The correct answer is: 

mRNA was discovered in the 1960’s and efforts to create vaccines using mRNA have been going on since the 1970’s

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mRNA vaccines work by introducing a live virus into the body.

True
False

The correct answer is: 

mRNA vaccines do not introduce any virus to the body (live or weakened). Instead it provides the instructions for the body to create an antigen using our natural internal processes.

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mRNA administered to the body through a vaccine enters the nucleus of a cell.

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False

The correct answer is: 

The mRNA that enters the body through a vaccine enters the cell, but it does not enter the nucleus of the cell where the DNA is stored.

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References

1 Deoxyribonucleic acid (DNA) Fact Sheet. National Human Genome Research Institute. (2023) (Page (Deoxyribonucleic acid (DNA) Fact Sheet, Paragraph 9, Line 1)
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2 Messenger RNA (MRNA). National Human Genome Research Institute. (2023) (Page (Messenger RNA(MRNA), Paragraph 1, Line 2)

3 How Many Human Proteoforms are There? Nature Chemical Biology (2019)(Page 1, Paragraph 2, Line 2)
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4 How Vaccines Work to Prevent Infections. American Journal of Respiratory and Critical Care Medicine (2021)(Page 1, Paragraph 1, Line 9)
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5 Understanding How COVID-19 Vaccines Work. Center for Disease Control. (2023) (Page 1, Paragraph 4, Line 2)
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6 Antigen. Cleveland Clinic (2022). (Page 1, Paragraph 2, Line 1).
7 mRNA Vaccines for COVID-19: What, Why and How. International Journal of Biological Science (2021). (Page 1, Paragraph (RNA Degredation), Line 4)

8 Expression kinetics of nucleoside-modified mRNA delivered in lipid nanoparticles to mice by various routes. J Control Release (2015) (Table 1).

9 The Tangled History of mRNA Vaccines. Nature (2021) ((Page (the beginnings of mRNA), Paragraph 1, Line 5)

10 Lipid Nanoparticles – From Liposomes to mRNA Vaccine Delivery, a Landscape of Research Diversity and Advancement. ACS Nano (2021)

11 The Tangled History of mRNA Vaccines. Nature (2021) (Figure 2)

12 Vaccines 2020: The Era of the Digital Vaccine is Here. Science Translational Medicine. (2021) (Page (The next frontiers for vaccines) Paragraph 1, Line 12)

CA-MRNA-2300015          04/2023
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