Myth: mRNA vaccines can alter your DNA

 Can mRNA vaccines alter my DNA? 

The ultimate answer to this question is no: mRNA vaccines cannot alter or change your DNA. 

The Cell

Before we discuss why mRNA can’t change DNA let’s talk about the cell. The cell is the body’s basic building block. Cells can look different and can have different functions but each cell has the same basic characteristics: 

1. 
   A cell membrane: a layer that envelops the inside of the cell and divides it from the outside of the cell. 
2. A nucleus: a small compartment within the cell where DNA is stored. Think of it like your brain; the nucleus is responsible for making instructions for activities that the cell has to do to stay alive. These instructions are found in the DNA. The nucleus is a highly protective housing for DNA and very little can get into it. 
3. Ribosomes: small proteins whose job is to take the instructions from DNA and execute them. 
4. Enzymes: proteins that are responsible for a large amount of jobs including destroying old instructions and helping DNA make the instructions that the cell can read. 

There are a lot of other parts of the cell but the four that we're going to focus on to answer this question are those listed above. 

So how does DNA instruct the cell to do something? The first thing DNA has to do is it has to get out of the nucleus; but, DNA cannot leave the nucleus. Instead the DNA sends a letter to the cell with instructions on how to do the job that needs to get done. The problem is that the cell can't read the letter unless the letter has been translated. This is because the cell can't understand DNA code. Therefore, inside the nucleus the DNA gets translated into Messenger RNA (mRNA). It does this with the help of enzymes which translate the DNA code into mRNA code. The mRNA code is then able to exit the nucleus and go to its destination: the ribosomes. At this point the ribosomes then read the letter and follow the instructions, which are usually to make a certain type of protein. After this process the mRNA is degraded almost immediately by enzymes. 

So the whole process goes: 

This process can only go in one direction. Proteins cannot make mRNA and mRNA cannot make DNA. There are certain bacteria and viruses that are specially evolved to have certain enzymes that can make DNA from RNA. However, humans do not have that enzyme so humans cannot take mRNA and make DNA. 

mRNA Vaccines

The mRNA vaccine contains RNA code that is enveloped in a cell membrane. In order for mRNA to get into your cells the cell membrane of the vaccine in your cells have to fuse together like when two bubbles converge into one bigger bubble. When that happens the letter containing the mRNA enters your cell and finds a ribosome. The ribosome then reads this instruction and makes the protein that it is told to make. 

In the case of the COVID-19 vaccine, the ribosome makes a SARS-CoV-2 spike protein, which the cell then recognizes as foreign and creates an immune response. Once the spike protein is made the mRNA is degraded. As mentioned before humans do not have the ability to make DNA from mRNA because we can't translate mRNA code into DNA code. 

Therefore mRNA vaccines cannot alter your DNA for the following reasons: 

1. mRNA cannot make DNA because humans lack the enzyme to translate mRNA code into DNA code 

2. The nucleus is a highly protective housing for DNA and very little can get into the nucleus. So DNA         is very well protected. 

3. Once mRNA has done its job it is destroyed. 

More information: 

CDC Covid-19 Vaccine information

DNA to RNA to Proteins