Another reason to get behind mandating that employees get paid sick days: Ensuring that all employees in the US have paid sick leave would reduce the spread of flu, a new study published in the American Journal of Public Health shows.

Researchers from the University of Pittsburgh Graduate School of Public Health simulated a flu epidemic in Pittsburgh and Allegheny County, using figures from the US Bureau of Labor Statistics on the number of people with paid sick days and the probability of them actually using them. The models suggest that if all employees had access to paid days off, the rate of spread of flu would drop 6 percent. The impact was greater at small companies than large, as smaller companies are less likely today to offer paid leave than large.

More dramatically, the study also examined the effect of companies offering employees extra days specifically when they have the flu. Allowing employees one extra "flu day" above and beyond other general sick days decreased the rate of spreading the illness by more than 25 percent; granting employees two flu days decreased flu infections by 40 percent. In both cases this policy was more effective at large companies (defined as having more than 500 employees) than at small ones.

The rationale behind granting additional flu days is that it would encourage employees to take more time off when they have the flu, enabling them to take heed of the Centers for Disease Control and Prevention recommendation to stay home from work for a full 24 hours after the fever breaks.

Though a growing number of places in the United States are trying to mandate paid sick leave, as a whole the nation dramatically lags behind the rest of the wealthy nations in the world in this regard. It is the only one of the 22 wealthy nations examined by the Center for Economic and Policy that does not provide sick leave for employees undergoing a 50-day cancer treatment; and, it's the only 1 of 3 nations not providing at least 5 days of leave for people sick with the flu.

In fact, the US lags behind virtually the entire world in ensuring that workers can take time off while sick. According to Labor Notes, under national law in 136 countries employers must provide at least 7 paid sick days annually—that's 70 percent of all nations. In 81 nations employees must be kept on the payroll if they suffer an illness lasting 26 weeks or longer. In 51 nations, while on sick leave you must get at least 75 percent of your pay, with 31 of those mandating full pay while out ill.