I think we DO know what they contain:
Pfizer/BioNTech COVID-19 mRNA Vaccine BNT162b2 contains:
This vaccine contains potassium, less than 1 mmol (39 mg) per dose, i.e. essentially ‘potassium-free’.
This vaccine contains less than 1 mmol sodium (23 mg) per dose, that is to say essentially ‘sodiumfree’.
The active substance is BNT162b2 RNA.
After dilution, the vial contains 6 doses, of 0.3 mL with 30 micrograms mRNA each.
This vaccine contains polyethylene glycol/macrogol (PEG) as part of ALC-0159
The other ingredients are:
ALC-0315 = (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)
ALC-0159 = 2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
1,2-Distearoyl-sn-glycero-3-phosphocholine
cholesterol
potassium chloride
potassium dihydrogen phosphate
sodium chloride
disodium hydrogen phosphate dihydrate
sucrose
water for injections
===
AstraZeneca COVID-19 Vaccine contains
This medicine contains less than 1 mmol sodium (23 mg) per dose of 0.5 ml. This means that it is essentially ‘sodium-free’.
This medicine contains a very small amount of alcohol (2 mg of alcohol (ethanol) per dose of 0.5 ml). This is not enough to cause any noticeable effects.
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 glycoprotein. Produced in genetically modified human embryonic kidney (HEK) 293 cells.
This product contains genetically modified organisms (GMOs).
The other excipients are:
L-histidine
L-histidine hydrochloride monohydrate
magnesium chloride hexahydrate
polysorbate 80 (E 433)
ethanol
sucrose
sodium chloride
disodium edetate dihydrate