EXPLAINER: How does the COVID-19 vaccine work?

Updated: Dec. 15, 2020 at 8:35 AM EST
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COLUMBIA, S.C. (WIS) - The mRNA vaccine for COVID-19 being rolled out across the country has caused a stir online as people try to understand how the science behind it works.

So WIS reached out to health experts who helped us break it down in a way that’s not too hard to understand.

“You can teach biology undergrad folks to make mRNA vaccines,” Dr. Helmut Albrecht, the chair of the Prisma Health-UofSC Medical Group said.

However, Albrecht noted scientists weren’t sure how effective it would be at creating an immune response against COVID-19 until pharmaceutical companies began releasing their trial data.

In the Pfizer coronavirus vaccine, mRNA -- or messenger RNA -- carries in it a blueprint for cells to create spike proteins.

COVID-19 vaccine
COVID-19 vaccine(COVID-19 vaccine)

The mRNA is programmed to go into the patient’s body and find the cells in their muscles.

COVID-19 vaccine
COVID-19 vaccine(COVID-19 vaccine)

Once inside the cell, the mRNA puts the body to work by teaching it to make spike proteins similar to the part of the coronavirus that attaches itself to other cells.

These spikes are not the part of the virus that makes people sick.

COVID-19 vaccine
COVID-19 vaccine(COVID-19 vaccine)

Once it is done producing spike proteins, the mRNA is destroyed without changing the patient’s DNA at all.

Then, antibodies and immune cells begin forming to fight off the spike proteins.

COVID-19 vaccine
COVID-19 vaccine(COVID-19 vaccine)

With an immune response created, researchers have found the Pfizer vaccine and vaccines like it to be nearly 95% effective at preventing people from contracting COVID-19. Doctors have applauded the vaccine as a safe way to prevent people from getting seriously ill from the virus.

“It is not a live vaccine, it cannot cause the disease itself and the messenger RNA can not code for anything it can not code for and doesn’t stick around the body to code for anything else over any other duration of time,” pediatric specialist Dr. Deborah Greenhouse said.


When explained to children, they understood the importance of this vaccine in less than a minute.

“The vaccine that is going into us isn’t dangerous and our body will know how to fight the real COVID,” 11-year-old Rebecca Allen said after hearing the basics about the vaccine. “The COVID vaccine tells the body how to fight it off,” her sister Audra, 9, added.

But like many people, some kids wondered whether a vaccine with mRNA would change their bodies at all.

“I asked the question if the vaccine would give me a horn but I found out that once the body gets the message it just disappears,” 12-year-old Saniyah Johnson said.

Again, mRNA vaccines cannot alter a person’s DNA.

There are, however, still some lingering questions scientists are trying to answer regarding the mRNA vaccine.

“What we don’t know is how long this incredible protection will actually last and how often you need to boost it,” Dr. Albrecht said.

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