Norovirus Infection Guidelines

Epidemiologic Evidence

Norovirus causes an estimated 21 million illnesses per year in the United States, making it the most common cause of gastroenteritis across all age groups 1
Norovirus accounts for 58% of gastroenteritis illnesses overall, far exceeding other pathogens, according to the Centers for Disease Control and Prevention (CDC) 2
Recent studies demonstrate that norovirus is the leading cause of acute gastroenteritis in the community and among persons seeking care in outpatient clinics or emergency departments across all age groups, as reported by the CDC 1
Systematic reviews estimate that noroviruses account for 10%-15% of severe gastroenteritis cases in children aged <5 years and 9%-15% of mild and moderate diarrhea cases among persons of all ages, according to the CDC 1
In the post-rotavirus vaccine era, norovirus has replaced rotavirus as the leading cause of acute gastroenteritis in vaccinated children, causing nearly 1 million ambulatory care visits and 14,000 hospitalizations annually, as reported by the American Academy of Pediatrics 2

Norovirus is the predominant cause of gastroenteritis outbreaks worldwide, responsible for approximately 50% of all reported gastroenteritis outbreaks (range: 36%-59%) in the United States and European countries, according to the World Health Organization (WHO) 1
The majority of norovirus outbreaks involve person-to-person transmission, though foodborne transmission accounts for approximately one quarter of the 21 million annual illnesses, as reported by the CDC 1

While rotavirus historically was a major cause of gastroenteritis, widespread rotavirus vaccination has dramatically reduced its burden, according to the American Academy of Pediatrics 2
Rotavirus vaccines prevent most severe disease, with documented effectiveness in reducing rotavirus disease by two-thirds, as reported by the CDC 2
Caliciviruses, astroviruses, and adenoviruses account for much smaller proportions of gastroenteritis cases compared to norovirus, according to the CDC 4, 5

Norovirus infections are highly contagious, requiring as few as 10 viral particles to cause infection, as reported by the American College of Gastroenterology 2
The virus demonstrates remarkable environmental stability and can remain infective even if frozen for years or heated to 60°C for 30 minutes, according to the CDC 4
Hand hygiene with soap and running water for a minimum of 20 seconds is the most effective method to reduce norovirus contamination, as recommended by the Centers for Disease Control and Prevention (CDC) 6
Ill healthcare workers, food handlers, and childcare workers should be excluded from work until 48-72 hours after symptom resolution, as recommended by the American College of Occupational and Environmental Medicine 6