The employee should not be permitted to return to the workplace and must be put on leave until they have recovered from the COVID-19 virus and are considered free of the COVID-19 virus. When the employee is ready to return to work, you can require from the employee a medical certificate that will state that the employee is free from the COVID-19 virus and can resume work.
Public health authorities directive is that all employees who worked closely with the infected employee should also be removed from the workplace for at least a 14-day period to ensure the infection does not spread in the workplace. As a result, these employees will also be put on leave so they can go into self-isolation of 14 days.
What constitutes “closely” will depend on the workplace and the nature of interactions between employees. Employers should err on the side of caution when determining closely.