They apparently use what are called "replication-incompetent" or "replication-deficient" vectors: adenoviruses that have been genetically modified to be incapab

They apparently use what are called "replication-incompetent" or "replication-deficient" vectors: adenoviruses that have been genetically modified to be incapable of (or not very good at - I'm not sure) replicating. Importantly, the vaccine does not use SARS-CoV-2, even in a weakened form. It just presents a SARS-CoV-2 spike protein.