Follow these steps:
1) Make sure reporting Absence rules are in place (eg. staff must telephone their boss by 8am)
2) Record sickness absence data meticulously
3) Return to Work Interviews are held after every single absence and are documented.
4) Review generous Company Sick Pay benefits
5) Put triggers in place for formal action against unacceptable Absence levels (eg. 2 or more absences in any 4 weeks will result in a warning)
Regular reviews of Company-wide sickness absence data will tell you how much sickness absence is eating away at your profits.