Yes - in science, definitions change all the time. We redefined what a planet was and booted Pluto out of the group.

Which part of the new definition do you disagree with as being a valid definition for a modern vaccine? And what difference does it make functionally? The covid vaccines were a product that gave you protection against a disease. Everyone knows that's what a vaccine is. I don't see why it matters what the definition on the site was to begin with.