"This is the first randomized trial to show that hand sanitizer reduces the spread of germs in the home," says Dr. Thomas J. Sandora, a physician in the Division of Infectious Diseases at Children's Hospital Boston and lead author of the study, dubbed "Healthy Hands, Healthy Families."

The families were recruited through day care centers, and all had a least one child in day care. Families already using hand sanitizer were excluded from the study. Half the families were randomly assigned to receive hand sanitizer and educational materials on hand hygiene. They were told to place bottles of the gel around the house, including bathroom, kitchen and baby's room, and to apply it to their hands after using the toilet, before preparing food, after diaper changes, etc. The remaining families, serving as controls, received only materials about nutrition, and were asked not to use hand sanitizer. The two groups reported similar rates of handwashing on an initial questionnaire.

For five months, investigators tracked the families, phoning every other week to record how much hand sanitizer had been used, whether someone had developed a respiratory or GI infection, and whether the illness had spread to others in the home. The families given hand sanitizer had a 59 percent lower incidence of secondary GI illnesses as compared with the control group, after adjustment for other factors such as the number of young children in the household.