So, as a confessed science nerd let me tell you what is going on in my arm and in my body since I got my shot on December 14th. The active ingredient of the Pfizer and Moderna vaccines is lipid (fat) covered messenger ribonucleic acid (mRNA), a few drops of which was injected into my left arm.
My immune system, ever at the ready, immediately recognized that something had happened: injury to my muscle and something weird that shouldn’t be there. It sent neutrophils and macrophages (professional immune cells) to check out the security breach and supervise repairs. Their job is to phagocytize (eat) the suspicious material and see if it is dangerous or not.
Surprise! A little mRNA Trojan horse has entered the cells and before it is efficiently destroyed by enzymes it gets the ribosomes (protein factories) to make a little bit of the coronavirus spike protein (the trick the virus uses to infect your cells).
The cells making the spike protein are beyond weird and my immune system leaps into high gear to do two things. One is to kill the abnormal cells. (Hence the soreness in my arm for a couple days.) Two is to get information about the weirdness to prepare my body in case this ever happens again. T cells and B cells (lymphocytes) examine the strange protein, learn how to recognize it, and teach cells to make antibodies and destroy any cells that display it in the future. (The reason why I may have more of a reaction to my second vaccine dose). These antibodies are quietly being produced in my lymph nodes as I write this. They will get stronger over a couple of weeks and stronger still after the booster shot in 3-4 weeks.
So when the SARS CoV 2 virus with her pretty little spike proteins comes to visit she will be greeted by an army of cells that already knows her trick and is ready to send her packing.
How cool is that!!
In part 3 I’ll dive a bit more into the chemistry of the vaccine and the purpose and risks of its inactive ingredients. Till then, mask up, wash your hands, physically distance and reach out to those who are isolated. We will get through this together.