The shortage of flu vaccine is causing concern among companies and workers about missed days of work due to illness. This is particularly troubling for the half of the American workforce that doesn't have paid sick leave, and loses money for each day missed. Public health experts point out that this leads many employees to feel that they must work even when they are sick, which contributes to the spreading of illnesses.
See "Lost to the Flu: Paydays", Amy Joyce, The Washington Post, October 14, 2004