Any business — if there are any — that can legitimately require immunization or antibody records of its employees — is already doing that. Maybe there are companies involved in medical research in sterilized environments that can justify this. Anyone else who tries this is quickly going to be out of business.
I worked at a hospital. If I could not document a vaccine...they did tests. I got more shots that week than I ever had. And tests and shot every year. TB and Hepatitis tests, and flu shots.
I had a “slight” outbreak of shingles. 15 days paid leave and I had to get proof I was clear.
I don’t expect that kind of surveillance in the average office. I would expect documentation being required to be cleared before going back. Especially for older employees. The lawsuits are going to be crazy.