It took just 48 hours for Ben Lopman’s 18-month-old son to go from being an energetic toddler to totally listless. Subscribe to read this story ad-free Get unlimited access to ad-free articles and exclusive content. Lopman’s son Ruben was suffering from severe dehydration from rotavirus, one of the most common causes of diarrhea and vomiting in babies and children. He was so sick, he ended up in the hospital, desperately needing intravenous fluids to keep up his strength to battle the infection. Lopman, an infectious disease epidemiologist now at Emory University, was living in London when his son got sick. It was 2008, five years before the United Kingdom approved a vaccine to prevent the highly contagious virus. The boy eventually recovered. “It was scary,” said Lopman. “It also reminded me how severe this disease can be for any kid.” Ben Lopman’s 18-month-old son, Ruben, suffered from severe dehydration from rotavirus.Courtesy Ben Lopman Rotavirus, a seasonal virus similar to influenza, has been rising across the U.S. since January. With infection rates higher now than this …