If an employee is truly a designated telecommuter and permanently works from home (i.e., never comes into the office, does not go to client meetings, does not attend conferences, etc.), this employee does not reasonably pose a virus transmission risk to other employees. Thus, the decision to exempt them from a vaccine requirement would appear reasonable. For additional perspective, you may consider that the proposed OSHA standard specifically exempted from the vaccine or test requirements “workers who do not come into contact with others.”

Ultimately, this comes down to company culture. You will need to decide if the equity concerns you mentioned are potentially great enough to require the remote employees to be vaccinated even though they don’t pose a risk to their colleagues.