Replication-deficient adenovirus vectors containing a pathogen-specific transgene have been used as novel vaccines because of their ability to induce strong humoral and cellular responses. However, preexisting immunity might reduce the immunogenicity of vectors derived from human viruses, hence, use of simian adenoviruses might be preferable. COVID-19 Vaccine AstraZeneca, also known as AZD1222 or ChAdOx1-S (recombinant), was developed by the Oxford University, United Kingdom, and Astra Zeneca, and is a replication-deficient chimpanzee adenovirus-vectored vaccine expressing the full-length SARS CoV-2 spike glycoprotein gene.

SAGE background document AstraZeneca COVID-19 vaccine COVID-19