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Vaccine Answers

what's in the vaccines?


Also known as messenger ribonucleic acid, mRNA is the only active ingredient in the vaccine. The mRNA molecules contain the genetic material that provide instructions for our bodies to make a viral protein that triggers an immune response. The immune response prompts us to make the antibodies needed to protect us from infection if we are exposed to the coronavirus.


The following salts are included in the Pfizer vaccine and help balance the acidity in your body.

  • potassium chloride
  • monobasic potassium phosphate
  • sodium chloride
  • dibasic sodium phosphate dihydrate

The following lipids are included to protect the mRNA and provide a somewhat “greasy” exterior that helps the mRNA slide inside the cells.

  • ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis
  • (2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
  • 1,2-Distearoyl-snglycero-3- phosphocholine
  • Cholesterol

Basic table sugar is included to help the molecules maintain their shape during freezing.


Like the Pfizer BioNTech vaccine, Moderna’s also uses mRNA technology to build antibodies against COVID-19. Please see above.

The remaining ingredients work together to maintain the stability of the vaccine after it is produced:

Acids: Acetic acid
Acid Stabilizers: 
Tromethamine & Tromethamine hydrochloride
Sodium acetate
Sugar: Sucrose


The Moderna vaccine also requires lipids to help deliver the mRNA to the cells.

  • SM-102
  • 1,2-dimyristoyl-rac-glycero3-methoxypolyethylene glycol-2000 [PEG2000-DMG]
  • cholesterol
  • 1,2-distearoyl-snglycero-3-phosphocholine [DSPC]
Recombinant, replication-incompetent adenovirus type 26 expressing the SARS-CoV-2 spike protein

A modified and harmless version of a different virus (Adenovirus 26) is used as a “vector” to deliver the DNA gene sequence to produce the coronavirus spike protein. Once the modified adenovirus vaccine enters into the cells, the body of the virus disintegrates and the DNA material within it travels into the nucleus of the human cell where it is transcribed into mRNA. The coronavirus spike protein is then produced and displayed on the cell’s surface, prompting the immune system to begin producing antibodies and activating T-cells to fight off what it thinks is an infection.

Like the two mRNA vaccines, Johnson & Johnson’s vaccine also includes ingredients that work together to stabilize the vaccine after it is produced:

Acids: citric acid monohydrate
trisodium citrate dihydrate

  • 2-hydroxypropyl-β-cyclodextrin (HBCD)
  • polysorbate-80, sodium chloride

Other ingredients: ethanol

Vaccine Answers

How were the vaccines developed so quickly?

Researchers were not starting from scratch. COVID-19 is one particularly serious type of coronavirus, but it is not the only coronavirus. Hundreds of other coronaviruses exist, including four strains of the common cold. So, researchers could build off of research regarding other known types of coronavirus when COVID-19 appeared. Availability of resources, widespread public support, and existing vaccine technology all contributed to the rapid development of COVID-19 vaccines.  

Additionally, regulatory agencies prioritized COVID-19 vaccine research, further expediting the process. Once vaccines were developed, they went through a federal approval process called emergency use authorization, which is an established method to make medicines such as vaccines available during a public health emergency. On February 4, 2020, COVID-19 was declared this type of public health emergency.

Vaccine Answers

what are the short- and long-term risks?

Short-term side effects

Common short-term side effects include pain, redness and swelling around the injection site and potential for fatigue, headache, muscle pain, chills, fever and nausea. These side effects typically subside after a few days.

Severe side effects are very rare

The technology behind the COVID-19 vaccine is a pre-existing, well-developed technology and independent researchers as well as government entities such as the FDA continue to monitor the long-term safety and efficacy of the various COVID-19 vaccines.

Vaccine Answers

What is the risk of getting COVID-19 vs. the risk of serious illness from the vaccine? 

Not vaccinated

75% higher chance of getting COVID

If you're not vaccinated, you have about a 75% higher chance of getting COVID than the national average. That’s because the national average includes both people who are vaccinated and unvaccinated. When you just look at folks who are unvaccinated, the danger goes up dramatically. As of June 2021, more than 33 million Americans have had COVID-19, and over a half million have died (1, 2).


Chance of getting seriously ill: 0.012%

Your chance of getting seriously ill from the vaccine is about 0.012%. With 140 million people fully vaccinated in the U.S., that translates to 17,476 hospitalizations due to side effects from receiving a COVID vaccine. (Source: Calculations from data from VAERS and the CDC). 

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