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What are the Ingredients and Excipients in the COVID-19 Vaccines?

AstraZeneca COVID-19 vaccine ingredients (Source Gov.UK)

One dose (0.5 ml) contains: COVID-19 Vaccine (ChAdOx1-S* recombinant) 5 × 10^10 viral particles (vp)

*Recombinant, replication-deficient chimpanzee adenovirus vector encoding the SARS CoV 2 Spike (S) glycoprotein. Produced in genetically modified human embryonic kidney (HEK) 293 cells.



  • L-Histidine hydrochloride monohydrate

  • Magnesium chloride hexahydrate

  • Polysorbate 80

  • Ethanol

  • Sucrose

  • Sodium chloride

  • Disodium edetate dihydrate

  • Water for injections

mRNA vaccines by Pfizer-BioNTech and Moderna

Covid-19 vaccination has been a big topic and we were curious on the role of excipients in such formulations. Not surprisingly both Pfizer-BioNTech and Moderna (source FDA) have quite similar compositions: Active Ingredient, Lipids and a saline solution. Lipid (oil) “bubbles” are tiny bubbles of lipid (oil) surround and protect the mRNA so cells in your body can pick it up both vaccines have Cholesterol as part of the composition. The Saline (salt) solutions are also different. Pfizer-BioNTech uses a common type of saline called phosphate buffer solution, or PBS. Moderna uses a tris buffer which aims to make the pH level of the vaccine close to that of our bodies. (Kerry McGee, MD –

Pfizer-BioNTech COVID-19 vaccine ingredients (Source FDA) mRNA (nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2)


  • (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

  • Cholesterol


  • Potassium chloride

  • Monobasic potassium phosphate

  • Sodium chloride

  • Dibasic sodium phosphate dehydrate


  • Sucrose

Moderna COVID-19 vaccine ingredients (Source FDA )

mRNA (Nucleoside-modified mRNA encoding the viral spike (S) glycoprotein of SARS-CoV-2)


  • SM-102

  • 1,2-dimyristoyl-rac-glycero3-methoxypolyethylene glycol-2000 [PEG2000-DMG]

  • 1,2-distearoyl-snglycero-3-phosphocholine [DSPC]

  • Cholesterol


  • Tromethamine

  • Tromethamine hydrochloride

  • Acetic acid

  • Sodium acetate


  • Sucrose

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