In most states, including Illinois, all employees are employed “at-will” (unless an employee is given a written contract that guarantees employment for a specific period of time). What that means is that any employer can fire any employee, with or without notice and with or without a reason, so long as the employer doesn’t do so on an illegal basis. So, while an employer may not be able to force an employee to get vaccinated, an employer can likely fire an employee for refusing to do so, with certain …