For children with asthma, the common cold is the top trigger of symptom attacks. So in theory, cleaner hands at school could mean fewer colds being passed around - and fewer asthma attacks.
The findings are not, however, the final word, according to Lynn B. Gerald, a professor of health promotion sciences at the University of Arizona in Tucson who led the study.
That's because the trial hit an obstacle when the H1N1 "swine" flu epidemic broke out right at the study's outset: All of the schools in the trial became a lot more vigilant about clean hands, Gerald said.
Schools that weren't part of the hand-hygiene program started putting hand sanitizer on the list of school supplies given to parents.
"Hand sanitizer became ubiquitous in schools," Gerald said.
So, she told Reuters Health, it's hard to draw conclusions about whether hand sanitizers, added to old-fashioned hand washing, might prevent some asthma attacks.
The sanitizers and soap used in the trial were provided to schools for free by Akron, Ohio-based GOJO, which makes the Purell brand hand sanitizers.
GOJO "believes there is great benefit in establishing the effectiveness of hand hygiene interventions under real-world conditions and supports scientific studies that take that approach," the company told Reuters Health.
"We agree with the conclusion that the results of this study were highly confounded by increased overall hand hygiene practices, even in the usual-care schools, as a result of the H1N1 pandemic," they said in an emailed statement.
The findings appear in the Journal of Allergy and Clinical Immunology.
VALUE OF INVESTMENT UNCLEAR
Frequent hand washing is one of the keys to protecting yourself from colds and the flu, or from passing the viruses to other people. But soap and water are not always at the ready, and even in school bathrooms soap dispensers may be broken or empty - especially at low-income schools like the ones in this trial, Gerald noted.
Many schools already have hand sanitizer available. At some schools, that's all they use, Gerald said. But no one knows how effective the products are versus soap and water alone.
For the current study, Gerald's team randomly assigned 31 Alabama elementary schools to either follow a special hand hygiene plan or stick with their standard ways for one school year. The schools then switched groups for the following school year.
When schools were on the hand hygiene plan, they were given hand soap for the bathrooms, and alcohol-based hand sanitizer for the bathrooms and classrooms. Students were also taught about good hand hygiene.
Gerald's team then focused on 527 students who had asthma. They found that over the two years, kids had no fewer asthma attacks when their school provided soap, sanitizers and education.
Still, the swine flu outbreak muddied the waters, according to Gerald. Asthma attacks spiked across the schools in the fall of 2009, when the swine flu was at its peak. In October, 41 percent of asthmatic kids in both groups of schools had a symptom attack, versus about 25 percent in October 2010.