Bach Seat

The COVID-19 vaccine from Pfizer and BioNTech – known by the code name BNT162b, has been in use in the UK for a week and is starting to be deployed in the US. With the regulatory approval to move forward from the U.S. Food and Drug Administration we now have the most detailed info yet on what is in the new COVIID-19 vaccine. MIT’s Technology Review looked at the ingredients in Pfizer‘s (PFE) vaccine and provided some context from scientists and biotech entrepreneurs for those of us without a Ph.D. in organic chemistry. 

1- mRNA – Pfizer’s vaccine consists of actual genetic information from a virus in the form of messenger RNA, or mRNA, a type of molecule whose usual job is to transport copies of genetic instructions around a cell to guide the assembly of proteins. The authors describe mRNA as a long ticker-tape carrying instructions. It’s fairly delicate stuff, and that’s why Pfizer’s vaccine needs to be kept at around -100 °F until it’s used.

• Nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2

The new vaccine, delivered as a shot in the arm muscle, contains an RNA sequence taken from the virus itself; it causes cells to manufacture the big “spike” protein of the COVID-19 virus, which the pathogen uses to glom onto a person’s cells and gain entry. On its own, without the rest of the virus, the spike is pretty harmless. But your body still reacts to it. This is what leaves you immunized and ready to repel the real virus if it turns up.

The mRNA in the vaccine, to be sure, isn’t quite the same as the stuff in your body. That’s good because cells defenses’ are ready to chop up RNA, especially any that doesn’t belong there. To avoid that, what’s known as “modified nucleosides” have been substituted for some of the mRNA building blocks.

But Pfizer is holding back a little according to the article. The spike gene sequence can be tweaked in small ways for better performance, by means that include swapping letters. We don’t think Pfizer has said exactly what sequence it is using, or what modified nucleosides. That means the content of the shot may not be 100% public.

2- Lipids – The Pfizer vaccine uses lipid nanoparticles to encase the RNA. The nanoparticles are, basically, tiny greasy spheres that protect the mRNA and help it slide inside cells. Pfizer says it uses the four different lipids in a “defined ratio.”

• (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis (ALC-3015)
• (2- hexyldecanoate),2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide (ALC-0159)
• 1,2-distearoyl-snglycero-3-phosphocholine (DPSC)
• Cholesterol

The lipid ALC-0315 is the primary ingredient in the formulation. That’s because it’s ionizable—it can be given a positive charge, and since the RNA has a negative one, they stick together. It’s also a component that can cause side effects or allergic reactions.

The other lipids, one of which is the familiar molecule cholesterol, are “helpers” that give structural integrity to the nanoparticles or stop them from clumping. During manufacturing, the RNA and the lipids are stirred into a bubbly mix to form what the FDA describes as a “white to off-white” frozen liquid.

3 – Salts – The Pfizer vaccine contains four salts, one of which is ordinary table salt. Together, these salts are better known as phosphate-buffered saline, or PBS, a very common ingredient that keeps the pH, or acidity, of the vaccine close to that of a person’s body. You’ll understand how important that is if you’ve ever squeezed lemon juice on a cut. Substances with the wrong acidity can injure cells or get quickly degraded.

• Potassium chloride
• Monobasic potassium phosphate
• Sodium chloride
• Basic sodium phosphate dihydrate 

4 – Sugar – The vaccine includes sucrose – plain old sugar. In the Vaccine, It is acting as a cryoprotectant to safeguard the nanoparticles when they’re frozen and stop them from sticking together.

5 – Saline solution – Before injection, the vaccine is mixed with water containing sodium chloride, or ordinary salt, just as many intravenously delivered drugs are. Again, the idea is that the injection should more or less match the salt content of the blood.

6 – No preservatives – Pfizer makes a point of saying its mixture of lipid nanoparticles and mRNA is “preservative-free.” That’s because a preservative that’s been used in other vaccines, thimerosal (which contains mercury and is there to kill any bacteria that might contaminate a vial), has been at the center of social media posts claiming vaccines cause autism. The US Centers for Disease Control says thimerosal is safe; despite that, its use is being phased out. There is no thimerosal—or any other preservative—in the Pfizer vaccine. No microchips, either.

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To counter social media fake news that Bill Gates put tracking microchips in the shots, or that the vaccine contains luciferase, a glowing chemical from fireflies whose name makes some people think of the devil – Pfizer has delivered a vaccine and an “official vaccine ingredient list.”

Stay safe out there!

Related article

• Find Your Place in the Vaccine Line (New Your Times)

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.