It's a live attenuated vaccine, and we're engineering it to express SARS-CoV-2 antigens, which should trigger the production of protective antibodies by the immune system.

这是一种减毒活疫苗，我们通过生物工程让它表达 SARS-CoV-2 抗原，以此来触发免疫系统产生保护性抗体。

Protection from a live, attenuated vaccine typically outlasts that provided by a killed or inactivated vaccine.

减毒活疫苗的保护通常比灭活疫苗或灭活疫苗提供的保护更持久。

Because killed or inactivated pathogens can't replicate at all, they can't revert to a more virulent form capable of causing disease (as discussed above with live, attenuated vaccines).

由于已杀死或灭活的病原体根本无法复制， 因此它们无法恢复为能够引起疾病的毒性更强的形式（如上文对减毒活疫苗的讨论）。