How the New mRNA Vaccines for COVID-19 Work

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How the New mRNA Vaccines for COVID-19 Work

What is mRNA, Anyway?

  • Messenger RNA, or mRNA, is genetic material that instructs cells to make certain proteins.
  • The new COVID-19 vaccines carry the mRNA blueprint for building the spike protein that the coronavirus uses to invade human cells.
  • Important facts: The vaccines do not contain actual virus; they do not cause infection; and they do not alter your DNA.

What's the First Step?

  • The vaccine is injected into the muscle of your upper arm.
  • The vaccine particles, which are wrapped in an oily coating so they can enter cells, attach to muscle cells and release mRNA inside.
  • Your cells use the mRNA instructions to make spike proteins. Soon after, the cell breaks down the mRNA strand and disposes of it.

How Does the Body Respond?

  • The new spike proteins start appearing on the outside of your cells.
  • Your immune system thinks these harmless proteins are actual invaders. (They're not.)
  • In response, it starts churning out antibodies and T cells. If you're exposed to the real virus that causes COVID-19 in the future, these cells will attack and disable it.

How Long Does It Take?

  • It takes several weeks for your immune system to build its defenses against the virus.
  • The two mRNA vaccines currently in use require two doeses, several weeks apart, for best protection.
  • You may experience some mild-to-moderate symptoms after each dose, such as a sore arm, headache or muscles aches.

What's Next

  • About two weeks after your second shot, your body will be ready to protect itself from coronavirus.
  • It's still important to continue wearing a mask and social distancing to protect others who may not be vaccinated.
  • While the shots prevent you from getting sick, we don't yet know if they prevent transmission.


Want to learn more about who is eligible or find where to schedule an appointment?

or call the Arkansas Department of Health at 1-800-803-7847.

The information in this story is accurate as of press time and posting. To limit the spread of the coronavirus, it’s important to continue practicing social distancing (keeping at least 6 feet away from people outside your household) and washing your hands frequently. You should also be appropriately masked any time you’ll be in public. According to the CDC’s latest guidance, this means layering a disposable surgical mask underneath a snug-fitting cloth mask or placing a mask fitter over your cloth mask to ensure a tight fit. Because the situation surrounding COVID-19 continues to evolve, we encourage readers to follow the news and recommendations for their own communities by using the resources from the CDCWHO, and their local public health department.