Known COVID-19 Contraindications

As with other vaccines or drugs, allergies to any of the ingredients is a contraindication, or reason not to get a COVID-19 vaccine. 

The known components of vaccines will be added here and updated as we know them.  

Components of the Pfizer mRNA vaccine

What are the ingredients in the Pfizer-BioNTech COVID-19 Vaccine and are these exact ingredients represented in any other prescription or non-prescription drugs or products?

This vaccine contains:

  1. Active ingredient: a nucleoside-modified messenger RNA (modRNA) encoding the viral spike (S) glycoprotein of SARS-CoV-2. 
  2. Inactive ingredients:
  • Lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), [(polyethylene glycol [PEG])-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, and 0.2 mg cholesterol),
  • Electrolytes potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and
  • Sugar (sucrose)
  • The diluent, added to the vaccine for administration, is saline (Sodium Chloride)

There are no other vaccines currently on the market that have these exact ingredients. 

The Moderna mRNA vaccine which has not yet received EUA is based on a similar construct with a PEG-2000 lipid delivery system. At this time there are no cases of serious allergic reactions associated with the Moderna vaccine in the reported clinical trial data. 

Polyethylene glycol (PEG2000) is a component of the vaccine and anaphylaxis (severe, life-threatening allergic reaciton) to PEG has been rarely reported with PEG3350 (bowel preparations) and prescription medications such as methylprednisolone acetate (Depomedrol). 

If you think you have had anaphylaxis with one of these products, you should contact occupational health and your primary care physician, who can consult with our allergy service.