AstraZeneca does not produce an mRNA COVID-19 vaccine. Instead, they produce a viral vector COVID-19 vaccine. A viral vector vaccine uses a harmless virus to deliver a piece of the SARS-CoV-2 virus's genetic material into the body. This genetic material causes the body to produce a protein found on the surface of SARS-CoV-2, which triggers an immune response. AstraZeneca's COVID-19 vaccine, called ChAdOx1 nCoV-19, is a viral vector vaccine.