Pfizer uses messenger RNA (mRNA) encased in a lipid layer, which, until recently, had not been approved for use in a human vaccine. The AstraZeneca option is a viral vector vaccine, which uses a harmless chimpanzee adenovirus to deliver DNA into our cells. This technology is also new to the world of approved vaccines.
But it's important to note the rest of the ingredients in Australia's two approved coronavirus vaccines — both of which have undergone rigorous testing and clinical trials — are the same as those found in a typical vaccine, Monash University professor of pharmaceutical biology Colin Pouton said. "Apart from these main [newly developed] parts, everything else is fairly standard."