The CDC changed the definition of "vaccine", since, unlike previous vaccines, the COVID-19 vaccine did not produce immunity:

Yes, the CDC changed its definition of vaccine to be 'more transparent' https://www.king5.com/article/news/verify/coronavirus-verify...

> [T]he CDC changed its definition of vaccine from "a product that stimulates a person's immune system to produce immunity to a specific disease, protecting the person from that disease" to "a preparation that is used to stimulate the body's immune response against diseases."