Chronic persistent Norovirus in the immune-compromised host.

PURPOSE OF REVIEW: Norovirus is the most frequent cause of acute gastroenteritis globally, with increasing recognition of chronic infection among the immune-compromised. This review outlines the latest evidence on the pathogenesis, clinical features, and management of chronic norovirus infection in the immune-compromised host. RECENT FINDINGS: Persistent norovirus shedding occurs in patients with compromised immunity, including those with congenital immunodeficiencies, recipients of solid organ and hematopoietic stem cell transplants, and individuals receiving chemotherapy or immunosuppressants. Chronic infection contributes to significant morbidity via prolonged gastrointestinal symptoms and malnutrition. The host cellular immune response, especially T cell function, is key to viral clearance. Limited therapeutic options, including ribavirin, nitazoxanide, and immunoglobulin, have shown mixed results. Investigational antivirals such as favipiravir are under early evaluation. Diagnosis remains complex due to histopathologic overlap with other enteropathies. SUMMARY: Chronic norovirus infection in immunocompromised individuals remains an under-recognized and difficult-to-treat condition. Future progress requires development of evidence-based antiviral therapies, and effective vaccines to mitigate long-term morbidity.