Remember, sooner or later, you will be a patient, one way or another.
Paybacks are hell.
Learn them if you are not familiar with them. Don't hard-time your ill employee when he or she wants to use vacation and sick time owed to him or her to cover time off. Remember, becoming seriously ill can entail financial hardship. Control the rumor mill. Designate an official status-provider and let that person get and give bulletins as they happen.