Decoding Pfizer’s Covid-19 Vaccine Ingredients
People have started receiving doses of the BNT162b2 vaccine in the U.K. This article details the ingredients included in the vaccine.
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On December 8 a U.K. woman named Margaret Keenan became the first person to receive a Covid-19 vaccine. At age 90, Keenan marked the beginning of what will be a broad global effort to vaccinate people against Covid-19.
As doses make their way to the United States, this article details the ingredients included in Pfizer’s BNT162b2 vaccine.
The basics
BNT162b2, much like the vaccine being offered by Pfizer-BioNTech, is an mRNA vaccine made up of strands of RNA packed into lipid nanoparticles. These particles, when injected into the human body, will fuse to the cell membrane of human cells and allow the mRNA to gain access to the machinery needed to translate it into viral proteins. Once these proteins are generated, they are packaged and released outside of the cell.
Once the viral proteins are released, our immune system has the opportunity to generate antibodies against them.
Lipid nanoparticle technology
The core of the Pfizer vaccine is the mRNA molecule that encodes for the spike protein (more on this later). In order to get mRNA from injection into the cells of the body, it needs molecular escort. By itself, mRNA cannot freely cross our cell membranes. Lipid nanoparticle technology solves this problem by packaging mRNA — known as a transcript — into a complex vesicle of phospholipid molecules that are designed to fuse with our body’s own cell membranes.
The lipid nanoparticle wall of the BNT162b2 vaccine is made up of four different compounds:
- ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2- hexyldecanoate) — A proprietary phospholipid that makes up the basic structure of the nanoparticle wall. These molecules are modeled after native phospholipids found in living cells.
- 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide — Another commercially available phospholipid linked to polyethylene glycol.
