"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. In addition, families reporting higher amounts sanitizer usage (more than 2 oz in 2 weeks, indicating 4-5 uses per day) were about 20 percent less likely to transmit respiratory illnesses, but this effect didn't reach statistical significance.
"We think that's probably because people were more diligent about using the sanitizer after a GI-related incident, such as using the bathroom or vomiting, than after a respiratory incident, such as nose-wiping or sneezing," says Sandora, also an instructor at Harvard Medical School.
A related study from Harvard Medical School and Children's Hospital Boston, published in the April issue of Pediatrics, did observe a protective effect against respiratory illness among families who used hand sanitizer gels at their own initiative.
The alcohol-based gels, widely available in stores, do not require water and rapidly kill most bacteria and viruses on the skin. They are a convenient alternative for busy parents who are unable to get to a sink while caring for sick children.
According to the U.S. Census Bureau, more than 7.5 million children under age 5 are enrolled in day care, placing them at high risk for respiratory and GI infections, which they readily transmit to household members.
Although handwashing with soap and water is effective in reducing the spread of most infections, it requires access to a sink. In addition, there is evidence that rotavirus, the most common GI infection in the child-care setting, is not removed effectively by soap and water but is reliably killed by alcohol.