Should a workplace be allowed to subject an employee to disciplinary action (including discharge) if the employee does not return to work because that employee believes they may incur a higher risk of

Should a workplace be allowed to subject an employee to disciplinary action (including discharge) if the employee does not return to work because that employee believes they may incur a higher risk of severe illness due to exposure to Covid-19 infection? If so, should this apply to all employees who have that belief or should there be some underlying conditions (including age) for exempting only employees who meet certain criteria that would subject them to a higher risk of illness from Covid-19 exposure? Discuss all viable options and sides.

(Remember this is a law course so you must bring the law (especially the current law) into your paper (this may involve statutes, administrative rules, court cases, etc.) You should bring in original legal sources if applicable. This is a law class, so I do not just want your opinion. As this is a developing problem, you should also bring in any current or pending laws (states or federal, etc.) and possible challenges to these laws into your paper.