Messenger ribonucleic acid (mRNA)
Messenger ribonucleic acid, or mRNA, is the active ingredients in the vaccines — it’s what helps your body develop immunity.
mRNA is genetic material that contains the instructions for how our body makes the viral protein that triggers an immune system response to help fight or protect our body from infection in the future.
The instructions in this strand of mRNA tell our cells to make a “spike protein,” or a protein found on the outer wall of the coronavirus. Because the spike protein is like the tire on a car, and not the whole car itself, we cannot get COVID-19 from the spike protein alone.
However, our bodies recognize the spike protein nonetheless and begin to create antibodies specifically designed to fight COVID-19, if we ever encounter the real virus.
Before the COVID-19 pandemic, scientists had studied mRNA vaccines for decades in the hopes that this type of vaccine would be useful in the future. Then COVID-19 hit.
Unlike the production of some types of vaccine, which takes a relatively long time, mRNA vaccines just need the genome (genetic code) of the virus they’re intended to protect against.
The mRNA in the vaccine cannot interfere with the mRNA or other genetic material in your body. It’s designed to degrade in about one to two weeks, though the antibodies your body creates stick around long after the mRNA is gone (that’s how you fight off the virus).
Adenovirus type 26 expressing the SARS-CoV-2 spike protein
The Johnson & Johnson vaccine does not use mRNA, described above, to build an immune response against COVID-19. Instead, it uses a different virus, an adenovirus (the common cold), to show the body what COVID-19 looks like.
The adenovirus is modified so that it is not able to cause illness or create more viruses in the body. It is designed to deliver genetic information for the COVID-19 spike protein to human cells.
Similar to the mRNA vaccines, our own body’s cells then make the COVID-19 spike protein and begin to create antibodies specifically designed to fight COVID-19, if we ever encounter the real virus.
Lipids
If you remember back to biology class, you might remember that lipids are the scientific term for fatty substances.
Simply put, lipids are fats and oils. That avocado toast you had at brunch? It had lipids in it. The olive oil in your pasta? Lipids.
Most food contains lipids that the body then stores for energy. The membranes of the cells in our bodies also contain lipids.
In vaccines, lipids surround and protect the mRNA as it’s transported to the cell.
Name of lipid ingredient(s)
Moderna
- SM-102.
- Polyethylene glycol (PEG) 2000 dimyristoyl glycerol (DMG).
- 1,2-distearoyl-sn-glycero-3-glycero-3-phosphocholine (DSPC).
Pfizer
- (4-hydroxybutyl)azanediyl)bis(hexane-6, 1-diyl)bis(2-hexyldecanoate).
- 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide.
- 1,2-Distearoyl-sn-glycero-3-phosphocholine.
All
Other uses
Polyethylene glycol (PEG) is derived from petroleum and is commonly used in laxatives. It is also used as an inactive ingredient and stabilizer in other medications, skin creams and toothpastes.
Cholesterol is in all animal-derived foods. The body needs cholesterol to make cells, vitamins and hormones.
Acid and acid stabilizers
Acids are everywhere. Like lipid, acid is a molecule that is found in many of the substances we eat and drink. In foods, we associate acids with anything that tastes sour, such as lemons and limes.
You might associate acids with the pH scale — any substance that measures less than 7 on the pH scale is acidic.
Acids are also found naturally in the human body. Hydrochloric acid in our stomachs helps aid digestion, amino acids are needed to make proteins and fatty acids help grow and repair the body’s tissues.
In the COVID-19 vaccines, acids and acid stabilizers work to maintain stability of the shot.
Name of acid/acid stabilizer ingredient(s)
Moderna
- Tromethamine (acid stabilizer).
- Tromethamine hydrochloride (acid stabilizer).
- Acetic acid.
Johnson & Johnson (Janssen)
- Citric acid monohydrate (acid stabilizer).
- Trisodium citrate dihydrate (acid stabilizer).
Other uses
Tromethamine injection, also known by the brand name Tham, can be used as in injection form to treat metabolic acidosis by making the blood and urine less acidic.
Vinegar is made of acetic acid. Acetic acid may have naturally occurring concentrations in wines, aged cheeses and orange juice. It can also be a food additive/preservative and used to make vitamins, antibiotics, hormones and other organic chemicals.
Salts
We all know what salt is. But did you know salt comes in many forms?
What we call table salt (sodium chloride) is a mineral that is actually part of a larger class of salts (a type of chemical compound).
For the human body, salt is a vital electrolyte that helps transmit nerve impulses and fuels our muscles. Our health depends on the right balance of salts and fluids in our bodies.
Like acids and acid stabilizers, salts help maintain the stability of the COVID-19 vaccine. They also help balance the acidity in the body.
Name of salt ingredient(s)
Moderna
Pfizer
- Potassium chloride.
- Monobasic potassium phosphate.
- Sodium chloride.
- Dibasic sodium phosphate dihydrate.
Johnson & Johnson
Other uses
Sodium acetate can be used as seasoning and is often used to extend shelf life and balance pH of foods. It’s commonly used to give potato chips a salt and vinegar flavor. Sodium acetate is also used in many injectable drugs, including intravenous nutrition formulations.
Potassium chloride is commonly used in the medical setting as an injection and oral medication to prevent or treat low potassium levels. It can also be used as a salt substitute.
Monobasic potassium phosphate can be used as a food additive and buffering agent (which adjusts the pH of a substance). It can also be used in a medical setting to treat low phosphate levels or make urine more acidic (to prevent kidney stones).
Sodium chloride is the chemical compound that we call table salt. It is one of the most common fluids given intravenously in a hospital. It is also used in many nasal and ophthalmic (eye) products. It can be used to correct low sodium levels, as an inhalation product for cystic fibrosis, to dilute inhalers, as a genitourinary irrigation and more.
Dibasic sodium phosphate dihydrate is used in foods such as condensed milk, desserts and pudding. It can also be used as a laxative.
Sugar
Sucrose, or sugar, is a carbohydrate that is found in fruits and vegetables. It’s produced by plants through photosynthesis, the process of converting sunlight to energy.
Our bodies convert sugar in our food and drink into energy.
Sucrose helps maintain the stability of the vaccine, like other ingredients. It also helps the molecule keep its shape and keep the vaccine effective after it’s made.
Sucrose is found in all COVID-19 vaccines approved by the U.S. Food and Drug Administration. It isn’t listed under any ingredient names.
As you know, sucrose is a kitchen pantry staple that we use in our favorite sweets and treats.
Other components
There are a few other ingredients, which all appear in the Johnson & Johnson vaccine, that don’t fall under the chemical compounds listed above, like lipids and salts.
2-Hydroxypropyl-β-cyclodextrin (HBCD)
2-Hydroxypropyl-β-cyclodextrin (HBCD) is a compound that helps maintain the vaccine’s active ingredients in a stabilized liquid form that is used for the injection. HBCD contains glucose and starch.
It is used in other medications that are injected or taken by mouth and is also used in some cosmetics.
Polysorbate-80 (Tween 80)
Polysorbate-80 (Tween 80) is used to stabilize and emulsify the vaccine. It is used in many other vaccines in the U.S., including tetanus vaccines, influenza vaccines, meningitis vaccines and commonly-used childhood vaccines.
Ethanol
Ethanol, or alcohol, is used as a solvent to help dissolve other ingredients in the vaccine.
Ethanol is used in plenty of medications and hygiene products, including mouthwash and cough and cold medication.
It is also the same chemical compound found in alcoholic beverages.
A Note on Ingredients and Allergic Reactions
Those who have had an allergic reaction to any ingredient in the COVID-19 vaccines should consult their doctor to determine which one is safe for them. Read more on the CDC’s website.
