I’m thankful I was in group 1A for my hospital system’s vaccine roll-out. I received my first dose of the Pfizer-BioNTech COVID-19 vaccine on December 18, 2020 followed by my second dose exactly three weeks later on January 8, 2021. In this post, I’ll discuss the ingredients and my symptoms following vaccination.
INGREDIENTS
The Pfizer-BioNTech COVID-19 multiple dose vaccine vial contains a frozen suspension with the following ingredients:
- Modified mRNA coding for SARS-CoV-2’s spike protein
- Lipids: ((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, and cholesterol)
- Salts: potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate
- Sucrose (table sugar)
This suspension is thawed either in a refrigerator or at room temperature. 1.8 cc of 0.9% sodium chloride (“normal saline”) is added as a diluent which, when combined with the aforementioned salts, creates a solution with optimum pH for mRNA stability. Each vial of the vaccine contains 5 doses of 0.3 cc. The lipid shell encapsulates the mRNA allowing it to be delivered into cells without early degradation.

The mRNA is utilized by normal cellular machinery (ribosomes, tRNA, etc.) to synthesize the spike proteins which are presented on the cell surface eliciting an immunologic response via antigen presenting cells, T helper cells, B cells, etc. Remember, these mRNA vaccines do NOT contain SARS-CoV-2, and therefore, cannot give you COVID-19. They also cannot alter your genetic makeup.
SYMPTOMS FOLLOWING VACCINATION
On December 18th, I was on call in the OR and received the vaccine around 12:30 PM. I went on with the work day but noticed my arm starting to get sore around 5:00 PM, and I felt a bit warm. By the time I went home that evening around 9:00 PM, my arm was a bit more sore. I didn’t have any issues overnight (nor was I called in, lol), and by the next morning, I was asymptomatic.
On January 8th, I had my second dose at 8:30 AM after giving a lecture to my fellows. I had come off a long week on service as an intensivist in a COVID-ICU, so I was particularly exhausted that day. Around 4 PM, I started having mild arm soreness in the site of injection. By 8:00 PM, this soreness got worse. I went to bed around 11:30 PM, but woke up at 1:00 AM with fever, headache, myalgias, weakness, and shivering that lasted for a few hours. I ended up taking 1,000 mg of Tylenol. I woke up at 5 AM, still had mild myalgias, a headache, and a subjective mild fever, but felt better after another dose of Tylenol.

What symptoms did you have? Which vaccine did you take? Drop me a comment with your experience regarding COVID-19 vaccination!



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