Since we're coming up on the Summer holiday season, I thought it only appropriate that I provide you with some heartening news that can be used to bolster your business continuity, physical security, and personnel security plans. Without going into too much detail, let's sum this up as such: healthier, happier employees will be more productive and represent a lesser risk to your organization. Hopefully this short missive can help you make a case for improved policies in your organization.
The first argument for this point is one that's been covered a lot in recent weeks in light of the bacon fever scare, so I'll just give it a cursory mention. Lumping sick leave in with paid time off (PTO) has a detrimental effect on productivity by encouraging people to come to work regardless of their physical or mental state. Within reason, sick leave should not be limited unless it becomes problematic. A liberal sick leave policy will actually increase overall productivity, not only in the afflicted employee, but also in the employees around them who may be distracted or, worse, may themselves become sick. The situation of people working all the time regardless of health or stress or conditions is called "presenteeism" and is covered in excellent detail in "Presenteeism: sick and tired at work".
The second argument is that, by removing sick leave from the PTO pool, vacation time would be effectively increased. However, I would recommend taking it one step further and automatically increasing the minimum threshold for time off proactively. Air New Zealand launched an ambitious study in 2006 on the topic (Vacation Gap Study), finding that people are more productive, healthier, and happier after time off, which has a strong benefit to the company.
Obviously these arguments need to be balanced against staffing/resource limitations. From a security perspective, both go directly toward business continuity, physical security, and personnel security planning. Happy, healthy employees are less likely to bail out without warning, are less likely to "snap" and enact retribution on the company, and are far more likely to be cooperative. Furthermore, advocating for a healthy work environment that discourages sick employees from coming into the office additionally strengthens the environment.