And you "know" they changed the definition, how? Because you read it on some antivax medical misinformation site, it must be true?
A vaccine is any compound that contains an antigen that induces the immune system to produce specific T-cells, B-cells, and antibodies that recognize the antigen. I don't care what any dictionary definition says, I only care about what the physical process is.
And you know the funny thing about antigens? They don't have to be associated with a pathogen at all. Most vaccines aren't even used in medicine, they are used to cause animals to make antibodies which are used in research.
As far as the science goes, all of the Covid vaccines are true vaccines.
Whatever you say.