How do mRNA Vaccines Work?

The main goal of vaccines is to train the body to recognize a virus as harmful and then protect us against it. Traditional vaccines have been made from a weakened or inactivated piece of virus that trains immune cells to recognize the real virus and create antibodies.

Instead, mRNA vaccines give your body a blueprint to produce (harmless) parts of a virus using your own cells’ mechanisms. This isn’t new technology; the first successful use in animals was published in 1990. But recent technological advances (e.g. novel RNA carriers, adjuvants) have made mRNA vaccines a reality.

Specifics of the COVID-19 mRNA Vaccines

The COVID-19 mRNA vaccines from Pfizer/BioNTech and Moderna give instructions for your cells to make part of the “spike protein.” The protein is made by your cells’ ribosomes and then displayed on the outside of your cells. The immune system sees the spike protein and makes antibodies. In the future, if you’re exposed to the virus, your body can quickly fight it off.

What mRNA vaccines DON’T do

The mRNA code is destroyed by the cell shortly after the protein is made. The mRNA never enters the nucleus of the cells where our own DNA is stored; therefore it NEVER interacts with or has the chance to disrupt our genetic code. Alos, these mRNA vaccines DO NOT use or create the live virus that causes COVID-19. So you can’t get sick with COVID from the vaccine.

(Image Source: BBC)


Last update: December 23, 2020 11:45 am ET
Science review: Initials ERS, JAB