What is an mRNA vaccine and how does it work?

According to the CDC, mRNA vaccines are a new type of vaccine to protect against infectious diseases. To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. mRNA vaccines do not work that way. Instead, they teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies.

  • According to the CDC, COVID-19 mRNA vaccines give instructions for our cells to make a harmless piece of what is called the “spike protein.” The spike protein is found on the surface of the virus that causes COVID-19. COVID-19 mRNA vaccines are given in the upper arm muscle. Once the instructions (mRNA) are inside the immune cells, the cells use them to make the protein piece. After the protein piece is made, the cell breaks down the instructions and gets rid of them.
  • Next, the cell displays the protein piece on its surface. Our immune systems recognize that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against COVID-19.
  • At the end of the process, our bodies have learned how to protect against future infection. The benefit of mRNA vaccines, like all vaccines, is those vaccinated gain this protection without ever having to risk the serious consequences of getting sick with COVID-19.

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1. I don't have access to a computer, how can I schedule an appointment?
2. I’ve already had COVID-19. Can I still get the vaccine?
3. What is an mRNA vaccine and how does it work?
4. What are the side effects of the COVID-19 vaccine?
5. How long will it take for the vaccine to begin protecting me?
6. With the availability of the vaccine does this mean the pandemic is over?
7. Can I receive a Moderna vaccine for my first shot and a Pfizer vaccine for my second shot?
8. Can I get COVID-19 from the vaccine?
9. Why can’t children under 16 receive the vaccine?
10. What does the Chester County Health Department do if there are doses left over at the end of a vaccine clinic?
11. Why should I get the COVID-19 vaccine?
12. Will the vaccine prevent me from getting COVID?
13. How many doses of the COVID-19 vaccine do I need to get?
14. What if I miss the second dose of the vaccine?
15. Will I need to receive the vaccine annually?
16. Do I still need to wear a mask after getting the vaccine?
17. I have a preference on which vaccine I receive. Can I submit my vaccine preference to the Health Department?