Related: An employer's guide to COVID-19 vaccines

Last March, the EEOC confirmed that the historical standard for vaccine policies still applied. However, the EEOC also advised: "Generally, ADA-covered employees should consider simply encouraging employees to get the influenza vaccine rather than requiring them to take it. As of the date this document is being issued, there is no vaccine available for COVID-19."

Past court decisions and guidance from the EEOC have confirmed that, in general, employers can require employees to receive vaccinations if they are job-related and consistent with business necessity, and if they allow for medical exemptions as required by the Americans with Disabilities Act and Title VII of the Civil Rights Act of 1964.

"Whether the job-related and business-necessity tests are met will depend on the nature of the business and an employee's duties," Muskovitz said. "This should not be difficult to establish." Employees with a qualifying disability that prevents them from safely receiving the vaccine may be entitled to an exemption from a mandatory vaccine policy. The employer has the right to request verification from an employee's health-care provider.

If employees' sincerely held religious beliefs or practices preclude them from receiving vaccinations, they may have a valid religious objection under Title VII. The beliefs do not need to be mainstream beliefs of any organized religion. The EEOC considers religious practices to include sincerely held moral or ethical beliefs as to what is right and wrong. However, political, medical or intellectual beliefs opposing vaccinations do not entitle an individual to a religious exemption.

"Once an employee requests an exemption, the employer must engage in an interactive process to determine if there is a reasonable accommodation that would not place an undue hardship on the company," he said. "An accommodation that would pose a direct safety threat to employees or third parties would amount to an undue hardship. A request for an exemption should be decided on a case-by-case basis.

"The bottom line is look for a mutually agreeable outcome to avoid termination and the risk that might come with it. And be sure to document all of the steps you take in the interactive process."

Lintemuth advises employers to gather as much information as they can before establishing a vaccination policy.

"There is not one clear path that enables an employer to avoid liability," she said. "There is a potential for liability whether or not you require or encourage employees to be vaccinated. The best way to avoid liability is to look for updated guidance and weigh the risk based on your industry, your employees and the risk of COVID-19 in your workplace."

She and Muskovitz shared several practical concerns to consider when setting policy:

• Employers may find that employees may react poorly to a mandatory vaccine policy.
• Vaccination policies should be consistently enforced so employees are treated like similarly situated employees.
• There are reports of some individuals experiencing flulike symptoms after the second injection.
• Whether or not you mandate or encourage vaccination, offer employees a trusted resource to provide knowledgeable, science-based information.
• Consider whether you will provide employees with paid time off to get vaccinated.
• Consider whether you will require employees to use accrued leave for absence related to an adverse reaction.
• If you are a unionized employer, review your collective bargaining agreement to determine whether this is a permissive or mandatory subject of bargaining.
• Be sure you are getting support from the top of the organization.

"There is not one right answer," Lintemuth concluded. "What is right for each employer depends on their industry, their workforce and the impact of COVID-19 on their business. Start developing a plan, but stay nimble. We expect updated guidance form the EEOC, OSHA and state and local authorities in coming weeks."