Subtoot: Hate to break it but proof of vaccination would not make return-to-office even remotely covid safe. Vaccines haven't been reliable for preventing covid infections for a very long time now and even when they do their efficacy plummets after a month or two. To make offices safe you would need both masking (N95 or better) and enough air filtration to get multiple air changes per hour. Those are the facts. That is what the science says