The United States is fighting a "quad-demic" this winter with four major viruses—COVID-19, influenza, respiratory syncytial virus (RSV) and norovirus—with infants at particular risk, Dr. Ryan Fulton recently warned. "This year, we've seen earlier and more intense surges of RSV and the flu compared to what we're used to," Dr. Fulton, section chief of general pediatrics at Carilion Children's Hospital and faculty member at the Virginia Tech Carilion School of Medicine, said in a statement. The U.S. Centers for Disease Control and Prevention (CDC) has reported an increase in visits to doctors on a scale not seen in 15 years....