"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.