A previous CDC definition of vaccination stated that they prevent disease.
Starting in 2015, the CDC's definition was revised to say that vaccines produce immunity, without necessarily preventing disease.
After the Covid-19 vaccines were introduced, and it was discovered they do not necessarily prevent disease nor provide immunity, the CDC edited "produce immunity" to say that the vaccines merely produce protection; which is no doubt the reason why vaccinated folk have to continue wearing masks because if the vaccines produced immunity and prevented disease, folks who've accepted the shots wouldn't require shielding.
State-operated electronic information signs placed along the highways in my area once advertised: "Save A Life. Get Vaccinated. It's Safe and Effective". A while back, the signs stopped urging vaccination.
I don't know why the State discontinued their message but they sort of had to seeing as how the CDC's definition of vaccination no longer contains the words "produces immunity and prevents disease" plus the fact that a growing number of deaths and adverse reactions related to the vaccines have demonstrated that promoting them as either safe or effective would be dishonest.