We will never know without an antibody testing. It can be under acceptable levels after having been vaccinated, too.

We have done such studies before with regarding to the hepatitis B vaccine. Most nursing students had no immunity against it after having received two doses of the vaccine.

I think antibody levels should be tied to the mandates. For what it is worth, I am against such mandates.

There's more to immunity than antibodies.

The body doesn’t keep antibodies around months after an infection but it knows how to create the antibodies if reinfection does happen. So of course a freshly vaccinated person will have more antibodies than a person who was infected months ago but that doesn’t mean the vaccine is more effective.