Management of Norovirus-Induced Vomiting and Diarrhea
Oral rehydration therapy is the cornerstone of norovirus management, with aggressive fluid replacement to prevent dehydration being the primary treatment goal, as norovirus gastroenteritis is self-limited and requires no specific antiviral therapy. 1
Immediate Clinical Management
Rehydration Strategy
- Initiate oral rehydration therapy immediately using solutions containing physiological concentrations of glucose and electrolytes to compensate for gastrointestinal losses and cover maintenance needs. 2, 3
- Oral rehydration is as effective as intravenous fluid therapy for mild-to-moderate dehydration and should be the first-line approach. 3
- For severe dehydration requiring hospitalization, intravenous fluid therapy is indicated with monitoring of serum electrolytes, creatinine, and glucose. 3
- Standard oral rehydration solutions (Pedialyte, Gatorade, or specialized formulations) are all effective, though hypokalemia may persist longer with Gatorade. 4
Symptom Management
- Consider ondansetron judiciously to increase the success rate of oral rehydration therapy and minimize the need for IV therapy and hospitalization, particularly in children. 3
- Avoid antimotility agents in immunocompromised patients as they may mask serious complications and aggravate ileus. 2
- For immunocompetent adults with nonbloody diarrhea, antimotility agents may be used as part of self-treatment. 1
Isolation and Infection Control Measures
Patient Isolation
- Isolate ill patients until 24-48 hours after complete symptom resolution in institutional settings including hospitals, long-term care facilities, and cruise ships. 1, 2
- Exclude ill healthcare workers, food handlers, and childcare workers from work until 48-72 hours after symptom resolution. 1, 2
- In licensed food establishments, obtain approval from local regulatory authority before reinstating food employees following required exclusion. 1
Hand Hygiene Protocol
- Promote frequent handwashing with soap and running water for a minimum of 20 seconds, as this is the most effective method to reduce norovirus contamination. 1, 2
- Alcohol-based hand sanitizers (≥70% ethanol) can be used as an adjunct between proper handwashings but should not substitute for soap and water. 1
Environmental Decontamination
- After initial cleaning to remove soiling, disinfect potentially contaminated surfaces using chlorine bleach solution with concentration of 1,000-5,000 ppm (1:50-1:10 dilution of household bleach 5.25%) or EPA-approved disinfectant. 1
- In healthcare settings, use EPA-registered cleaning products with label claims for healthcare use, adhering to manufacturer's instructions for dilution, application, and contact time. 1
Special Population Considerations
Immunocompromised Patients
- Obtain stool specimens during acute phase (≤72 hours from onset) for RT-qPCR diagnosis, as this is the most reliable diagnostic method. 2
- Perform genotyping on norovirus-positive specimens to identify viral strains and track transmission patterns. 2
- Test for Clostridioides difficile and its toxin in all cases, as immunocompromised patients face increased risk for C. difficile-associated diarrhea. 2
- Evaluate for other opportunistic pathogens including Cryptosporidium, Cyclospora, microsporidia, Cystoisospora belli, CMV, and MAC, particularly in HIV-infected patients. 1, 2
- Specifically request Cryptosporidium and Cyclospora testing, as standard ova and parasite examinations do not include these organisms. 1, 2
- Monitor closely for dehydration, electrolyte imbalances, and nutritional status, as chronic infection can lead to severe malnutrition and cachexia. 2
Elderly and Long-Term Care Residents
- Recognize that people >90 years of age in long-term care facilities have 20-30% increased risk of death and hospitalization during norovirus outbreaks. 1
- Patients who acquire norovirus while hospitalized, especially those with immunocompromising conditions and advanced age, may be more likely to die. 1
Pediatric Patients
- Most norovirus illnesses in children are self-resolving, but severe outcomes from dehydration including hospitalization and death can occur. 5
- Treatment focuses on early correction of dehydration and maintenance of fluid status and nutrition. 5
Clinical Course Expectations
Typical Timeline
- Symptoms begin 12-48 hours after exposure with acute onset. 6
- In immunocompetent individuals, symptoms typically last 12-72 hours with self-resolution. 6
- More prolonged courses of 4-6 days can occur in young children, elderly persons, and hospitalized patients. 1, 6
Transmission Considerations
- Peak viral shedding occurs 2-5 days after infection with approximately 100 billion viral copies per gram of feces. 1, 6
- Viral shedding can continue for an average of 4 weeks following infection, though infectivity beyond acute phase is unclear. 1, 6
- Up to 30% of infections are asymptomatic, yet these individuals can still shed virus at lower titers. 1, 6
Outbreak Management
Investigation and Reporting
- Initiate investigations promptly, collecting clinical and epidemiologic information to identify predominant transmission mode and possible source. 1
- Collect whole stool specimens from at least five persons during acute phase for RT-qPCR diagnosis, perform genotyping, and report results to CDC via CaliciNet. 1
- Report all acute gastroenteritis outbreaks to state and local health departments and to CDC via National Outbreak Reporting System. 1