A new study from partners of the Atlantic Alliance for Public Health, which includes Columbia University’s Mailman School of Public Health and France’s École des Hautes Études en Santé Publique (EHESP), looks at the collateral impact of the 2009-2010 A/H1N1 influenza pandemic and related public health measures on rates of diarrhea in France. Analysis of the unique natural experiment, published in the October edition of PLOS ONE, indicate that during the A/H1N1 pandemic, there was a six-week delay in the expected seasonal diarrhea epidemic, during which time there was a 24 percent decline in rates of the disease. This decline corresponded with increased sales of hand-sanitizing gels. Immediately following the pandemic, there was a 40 percent rebound in diarrhea rates that corresponded with decreased sales of hand sanitizer, although the rebound was significantly less pronounced in adults over age 65. Overall, the country had more than 570,000 additional diarrheal cases compared to previous years.