Diarrhea may be one of the most common human experiences, something that everyone suffers through multiple times in their life. Rich or poor, young or old, in developed nations or emerging countries, no one escapes bouts of diarrhea during their lifetime. Gastrointestinal infections leading to diarrhea can be caused by various microorganisms including protozoa, parasites, bacteria, and viruses. Among the viruses, a prominent culprit, especially in young children, is the rotavirus. Estimates suggest that by age five, almost all children, irrespective of country or socioeconomic status, will have had a rotavirus infection (Bishop 1996). It spares no one and infects everyone, hence its moniker as the democratic virus. Many children are infected in the first year or two of life when the disease can be most problematic. Symptoms begin after a short incubation period of 36–48 hours and start with fever, stomach pain, nausea, and vomiting. More concerning is the sometimes severe diarrhea that can persist from three to eight days. As adults, we typically find diarrhea vexing and inconvenient but not life-threatening. In contrast, extensive diarrhea in infants and toddlers can be a dangerous situation. With their small body mass and the difficulty in getting them to drink fluids, they can quickly become dehydrated from diarrhea and may need intravenous fluids to restore the electrolyte balance. In developing nations where medical intervention is unavailable and access to clean water is limited or nonexistent, rotavirus is a major cause of childhood mortality. Historically, rotavirus infections were associated with nearly a million deaths per year globally, predominantly in portions of Africa and Asia. This amounts to about 5% of all deaths in children under 5 years old each year, making rotavirus a major cause of early childhood mortality. Even in developed nations, rotavirus significantly impacts the healthcare system by causing hundreds of thousands of doctor visits and tens of thousands of hospitalizations yearly. Deaths, though rare, can occur when parents fail to recognize the seriousness of their child’s dehydration until too late. More insidious than the immediate effects is the potential damage to the gut incurred by repeated infections (Kolling et al. 2012). Gut damage can alter the microbiome and have long-lasting health consequences, including deficits in cognitive development. Before the vaccine, the U.S. alone had about 50,000 hospitalizations and 50 deaths annually from rotavirus, so a significant number of children were at risk each year for the immediate and long-term effects of GI infections.