If an employee raises concerns about co-workers being unvaccinated, it is important to highlight that vaccination is not mandatory (unless working in a profession with mandatory requirements as specified by your state or territory) or that they may have a medical exemption.
Whilst vaccinations are available to all, it may not be reasonably practical to require vaccinations in a workplace. Ensuring employee safety is about minimising the total risk of COVID-19 in the workplace, with vaccination being one way to do so. It is important to remind employees that whilst vaccination is encouraged, there are other control measures in place to manage the overall risk in the workplace.