The Center for Disease Control and Prevention recommends that “people with influenza-like illness remain at home until at least 24 hours after they are free of fever (100° F), or signs of a fever without the use of fever-reducing medications.” However, may employees in the U.S. either cannot take leave when they are sick or do not receive pay for doing so. A new report suggests that this lack of paid sick days may have contributed to the spread of H1N1 (previously known as Swine Flu) virus between September and November of 2009.

The report argues that “the United States is one of the few developed nations without universal paid sick days. The vast majority of public sector employees receive paid sick days, but two of five private sector employees have no access to paid sick days, leaving the nation ill-prepared for the H1N1 “swine flu” pandemic or for future outbreaks of contagious diseases.” The results show that almost 26 million employed Americans age 18 and older were infected with H1N1 during the peak months of H1N1 in 2009. Almost 18 million employees took at least part of a week off in response, which means that about 8 million employees went to work while infected.

There is a sharp difference between public sector and private sector employees: while more than 90% of public sector employees took time away from work when infected with H1N1, only 66% of private sector employees did the same. This implies that many more private sector employees felt that it was necessary to attend work while ill. The report also reveals that after the peak month of October, absences fell in November, but the drop in absence rates was twice as large in the public sector as it was in the private sector, thus suggesting that contagion was less common in the public sector because employees had stayed at home in the previous month. Private sector employees without paid sick days who have attended work while ill may have extended the duration of the outbreak in their companies.

While the report did not look at absences from school or child care, it is highly possible that parents who do not have sick days are less likely to stay home with their sick children. Therefore, those parents that did not keep their children at home while sick may also have contributed to the spread of the disease at their children’s day care or school.