Norovirus, a highly contagious stomach bug causing vomiting and diarrhea, is surging across the U.S. in early 2025. It is the leading cause of gastroenteritis nationwide. With outbreaks reaching record highs this winter, understanding norovirus symptoms and prevention is more important than ever.
What is Norovirus?
Norovirus is a group of viruses that cause acute gastroenteritis – inflammation of the stomach and intestines. People nickname it the “stomach flu,” but it remains unrelated to influenza, which affects the respiratory system. Norovirus infection gives only temporary immunity, so reinfection is possible because of many strains.