Issue: November 2017
October 05, 2017
3 min read

2nd-grade hand hygiene experiment reduces school absenteeism by 71%

Issue: November 2017
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SAN DIEGO — The CDC has described hand-washing as a “do-it-yourself” vaccine. Researchers here showed how it can prevent absenteeism due to illness among elementary school students.

According to findings presented at IDWeek, school absences plummeted 71% among second graders at a Virginia elementary school after researchers taught the students how to properly wash their hands, then culture them to detect microbial growth.

Kavita Imrit-Thomas, DO, associate medical director of LifeNet Health in Virginia Beach, Virginia, and colleagues gave the students a hands-on role in the experiment, which took place this past January.

“They were the scientists,” Imrit-Thomas said during a press conference announcing the findings. “Just to have the kids feeling and seeing and smelling the results of their experiment really made an impact.”

According to the CDC, 160 million school days are lost each year due to infectious illnesses — absences that may be avoided by hand-washing. Done properly, the CDC says hand-washing can help reduce the spread of diarrheal and respiratory illnesses.

For their experiment, Imrit-Thomas and colleagues instructed 90 second graders in five classes at a Virginia Beach public school how to wash their hands according to CDC recommendations. The five-step process instructs people to wash, lather, scrub, rinse and dry their hands.

They talked to the students about important times for hand-washing, such as before eating, after going to the bathroom and after blowing their nose, and placed posters near each sink to help the students remember the best way to clean their hands.

For the experiment, they had the students culture their hands in Petri dishes filled with agar and then separated them into two groups: half washed their hands with soap, and half used alcohol-based hand sanitizer. Afterward, the students re-cultured their hands.

According to Imrit-Thomas and colleagues, students and teachers observed an average overall decrease in microbial growth of 91% after 5 days — mostly of bacteria and mold — when looking at the cultures under a microscope. For one class, the decrease was 100%. In three of the classes, teachers noted that hand sanitizer gel appeared to be more effective than soap against microbial growth. In the other two classes, the results were similar.

The researchers used a simulation germ with black light to show students spots they missed while cleaning their hands. In addition to seeing a 71% decrease in school absences in the 30 days following the experiment, they said teachers reported observing, on average, an 89% improvement in hand-washing behavior among their students. Moreover, cultures from the hands of 10 students revealed an increase in resident skin flora, indicating a decrease in transient flora, which is most likely to cause illness, according to Imrit-Thomas and colleagues.

“There are a few noble truths about infectious disease. One is that kids get a lot of infections and they transmit a lot of infections. And the other is that hand-washing, as old and simple as it is, is one of our greatest tools,” Andrew T. Pavia, MD, professor and chief of the division of pediatric infectious diseases at the University of Utah, said during the press conference.

“But it’s rare that we get good scientific data that [look] at hand-washing and our ability to get people to do a better job of hand-washing and whether it makes a difference,” Pavia, who was not connected to the study, continued. “This (study) demonstrates those things.”

Imrit-Thomas said elementary schools should add hand hygiene experiments to their standard curriculum to teach and reinforce this lifelong healthy habit. They did not examine if their experiment had a broader effect on the health of the students’ families, but Pavia said those results could be extrapolated from other studies.

“Studies that have looked at vaccinating kids against influenza that have tried to measure the impact on parents and grandparents have shown that, if you block illness in the kids, you have an effect,” he said. – by Gerard Gallagher


Watson J, et al. Abstract 1332. Children learn about illness-causing bugs firsthand. Second-grade hand-washing experiment leads to big decrease in bacteria, illness. Presented at: IDWeek; Oct. 4-8, 2017; San Diego.

Disclosure: The researchers report no relevant financial disclosures.