Nandrup-Bus, Ange. American Journal of Infection Control, Vol. 39, Issue 6, August 2011.The objective of this study was to determine the effect of mandatory, scheduled hand disinfection (HD) on actual absenteeism because of infectious illness in elementary school pupils in Denmark. A three-month experiment compared one school in which students were required to wash their hands three times a day, with another where hand washing was not required. Hand-washing was shown to significantly decrease absenteeism.