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Q: I've read that the COVID-19 vaccine is a new kind of vaccine called mRNA. What does that mean?

In the past, many vaccines worked by using a small amount of inactive or weak virus to trigger an immune response. This taught the body how to fight the virus so that when the person was later exposed to live virus, they would not get seriously ill.

The mRNA vaccine, while considered new, is not unknown and has been studied for more than a decade. It works by teaching the immune system to fight a virus; however, unlike an inactivated vaccine, it doesn't contain any of the virus itself.

Instead, this vaccine delivers strands of genetic material called mRNA, contained inside a protective fatty coating. The term mRNA stands for "Messenger RNA." It includes instructions that show cells how to replicate part of the "spike protein" found in COVID-19. Once the immune system recognizes this protein, it develops antibodies to fight it. These antibodies then stay in your system so that your body is ready to fight off a real COVID-19 infection if you are exposed in the future.

Because the vaccine activates your immune system, some people experience side effects, including pain at the injection site, fatigue, muscle ache, headache, low fever, and chills. These side effects are a sign that your immune system is activated, and the vaccine is working.

It's impossible to get a real COVID infection from the vaccine because the mRNA only shows your cells how to replicate part of the "spike protein," not the virus itself.

The mRNA does not enter the cell nucleus or affect the body's own genetic makeup. The cell's enzymes naturally break down and remove the mRNA after the process is complete.

Each of the mRNA COVID-19 vaccines approved for emergency use by the FDA has been tested in around 40,000 people and has been found to be very safe.

Chrissy Miller
Employee Health Manager, Maui Health