"Knowing what an organization can or cannot do with respect to Covid-19 vaccines can help them keep their employees, students, and members safe and also save the them from costly and time-consuming litigation."
Employers can't require Covid-19 vaccination under an EUA - STAT
Organizations are free to encourage Covid-19 vaccination by employees and others, but federal law prohibits them from requiring it.
https://www.statnews.com/2021/02/23/federal-law-prohibits-employers-and-others-from-requiring-vaccination-with-a-covid-19-vaccine-distributed-under-an-eua/