How Does a COVID-19 mRNA Vaccine Work?

Traditional vaccines rely on weakened, partial, or dead viruses.

An mRNA vaccine does not contain any real virus at all. Here's how it works.


covid, questions, answers, vaccine, mrnaIn January 2020, scientists in China wrote out the 'genetic code' of the SARS-CoV-2 virus - the virus that causes COVID-19.

The genetic code of a virus tells us how the virus is made and helps us understand a little of how it works. 

They shared this code with scientists across the world with the hope that someone could find a cure for the virus.

covid, questions, answers, vaccine, mrnaThe spike protein is what makes the virus that causes COVID-19 infect us.

The spike protein is very strong, sticks to our healthy cells, and stabs its way through the protective barrier of our cells. The virus then uses our cells to make copies of itself, which makes us sick.

Scientists decided the genetic code for the spike protein was best for a vaccine.

covid, questions, answers, vaccine, mrnaScientist made their own fake mRNA. 

The fake, or synthetic, mRNA was made to deliver the recipe for the SARS-CoV-2 spike protein to our cells.

This mRNA is the main, active ingredient for the vaccine.

covid, questions, answers, vaccine, mrna

To be sure the mRNA makes it to our cells and can help us, scientists have to protect it.

They put it in a protective liquid in microscopic capsules.

The liquid uses similar ingredients to what is in our bodies - oils, salts, and sugars.

The liquid and the fake mRNA do not contain any biological ingredients and were not made using any biological ingredients.

covid, questions, answers, vaccine, mrnaThe COVID-19 vaccine is injected in the upper arm muscle, the deltoid.

Both the Pfizer and the Moderna vaccines require two doses of vaccine. Pfizer's second dose is 21 days later. Moderna's is 28 days after the first dose.

These two doses make sure our bodies learn how to fight the virus.

covid, questions, answers, vaccine, mrna

Once injected, the vaccine's fake mRNA delivers instructions to our cells.

The instructions tell the cells how to make fake spike proteins that look like the real SARS CoV-2 spike protein.

The cells use the instructions and make tons of fake spike proteins.

covid, questions, answers, vaccine, mrna

Our immune system reacts just like it should. It sees the fake spike proteins as dangerous intruders. 

Our immune cells figure out what these intruders are doing and creates defenses (antibodies) that will kill the spike proteins.

covid, questions, answers, vaccine, mrnaWhile destroying the fake spike proteins, our immune system learns what works and what the spike protein looks like. 

This is why you may feel some side effects after your vaccine, because your immune system is learning how to protect you from the virus that causes COVID-19.

After the second dose of vaccine, our immune system has learned and remembers how to kill SARS-CoV-2 if they ever see them again. 

Next... How Do We Know they Are Safe and Effective? 

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