Vaccines contain several ingredients with each one playing a necessary role toward maintaining the vaccine’s stability, safety and effectiveness.
With the COVID-19 vaccines produced by Pfizer-BioNTech and Moderna, the main ingredient of the vaccine is messenger RNA (mRNA).
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This new type of vaccine uses a genetic sequence to teach our cells how to make a piece of the spike protein that’s on the surface of SARS-CoV-2, the novel coronavirus that causes COVID-19, according to the Centers for Disease Control and Prevention (CDC).
Once the piece of spike protein is produced, it triggers an immune response inside our bodies. That immune response produces antibodies, which teach our body how to recognize and destroy the virus if we’re exposed to it in the future. The spike protein does not cause you to become ill with COVID-19.
While mRNA is the main ingredient of the Pfizer-BioNTech and Moderna vaccines, fatty lipid nanoparticles also play an important role in helping to deliver the mRNA to the body’s cells.
Other ingredients, like potassium chloride, sucrose (sugar) and acetic acid work to maintain the pH or stability of the vaccine, which is crucial in keeping the vaccine effective after the manufacturing process.
All of the ingredients work together to ensure the vaccine is effective and stable for when it’s ready to be injected.
What’s not in the vaccines?
The ingredients in vaccines that make them safe and effective in battling infectious diseases are important to know. But what’s even more important for us to know is what’s NOT in vaccines, particularly the COVID-19 vaccines manufactured by Pfizer-BioNTech and Moderna.
Karin Terry, PharmD, medication safety pharmacist for OSF HealthCare, and Brian Laird, PharmD, manager of Pharmacy Operations at OSF HealthCare Heart of Mary Medical Center, teamed up to offer insight into frequently asked questions they receive.
Q. Is there live COVID-19 virus in the vaccines? Can the vaccines give me COVID-19?
A. No, mRNA vaccines do not use the live virus that causes COVID-19. None of the COVID-19 vaccines currently authorized for use or in development in the United States use the live virus that causes COVID-19.
Q. What does the mRNA do? Will it affect my DNA?
A. These vaccines do not affect or interact with our DNA in any way. The mRNA of the COVID-19 vaccine tells our body’s cells how to build part of the spike protein on the coronavirus. This step is crucial in the development of antibodies against coronavirus. The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions. The mRNA never enters the part of the cell which contains our DNA and therefore cannot affect or change it.
Q. Can the Pfizer and Moderna vaccines be used in accordance with Catholic values?
A. The United States Conference of Catholic Bishops (USCCB) has provided a message to bishops, stating that it found no ethical problems with either the Moderna or Pfizer-BioNTech COVID-19 vaccines.
Q. I have an egg allergy. Can I safely get the COVID-19 vaccine?
A. Yes. A major advantage of mRNA vaccines is that mRNA can be produced in the laboratory from a DNA template using readily available materials. This makes it less expensive and faster than conventional vaccine production, which can require the use of chicken eggs or other mammalian cells. With mRNA vaccines, no chicken eggs or other mammalian cells are used.
Q. Is there a concern if I have a latex allergy?
A. No. The stoppers on the vials of the Pfizer-BioNTech and Moderna COVID-19 vaccines are not made with natural rubber latex.
Q. Are there preservatives in the mRNA COVID-19 vaccines?
A. Neither the Pfizer-BioNTech nor the Moderna COVID-19 vaccine contain preservatives.
Q. Do the vaccines contain microchips?
A. No. The COVID-19 vaccines do not contain microchips. A widely-shared conspiracy theory falsely claims that Bill Gates funded the vaccines to put microchips in people through vaccines. The vaccines contain a tiny piece of genetic material encased in salt, sugar and fats.
CDC guidance on allergic reactions
After receiving reports of allergic reactions to the COVID-19 vaccine, the CDC recommends the following if you:
- Have had a severe allergic reaction to any ingredient in a COVID-19 vaccine, you should not get that specific vaccine
- Have had a severe allergic reaction to non-COVID-19 vaccines or injectable therapies, speak to your health care provider about whether you should get a COVID-19 vaccine
- Have a history of severe allergic reactions unrelated to vaccines or injectable medications, you may still get vaccinated
- Have a history of allergies to oral medication, a family history of severe allergic reactions or have had a milder reaction to vaccines (not resulting in anaphylaxis), you may still get vaccinated
- Experience a severe allergic reaction after getting the first shot of a COVID-19 vaccine, you should not get the second shot
A full list of ingredients for the Pfizer-BioNTech vaccine can be found here. Moderna’s vaccine ingredient information can be found here.
What if I’m unsure what to do?
If you’re unsure if you’ve had an allergic reaction that applies to what the CDC has recommended, the best thing to do is talk with your health care provider about whether it’s OK to get the vaccine.
Last Updated: March 2, 2021