“Stomach bug,” “cruise-ship virus,” “winter vomiting disease”—all are nicknames for norovirus, the top cause of vomiting, diarrhea, and foodborne illness in the U.S. The contagious ailment typically circulates throughout the late fall, winter, and early spring, and the 2024–25 season is no exception. Nationwide test positivity was nearly 23% the week ended Dec. 28, compared to less than 11% six weeks earlier, according to the Centers for Disease Control and Prevention (CDC).
Up to 21 million people contract norovirus each year in the U.S. alone, the CDC says. Though most people recover from the gastrointestinal illness within three days, norovirus is annually responsible for 465,000 emergency department visits, mostly in young children; 109,000 hospitalizations; and 900 deaths, mostly among adults 65 and older. And unlike the other three illnesses that make up the ongoing “quad-demic”—flu, COVID, and respiratory syncytial virus (RSV)—norovirus has no FDA-approved vaccine.
