"…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." HARMLESS CHIMPANZEE ADENOVIRUS TO DELIVER DNA TO OUR CELLS. !!!! https://www.abc.net.au/news/health/2021-03-03/covid-19-pfizer-astrazeneca-vaccine-ingredients-components/13137240