Norovirus Infection in Transplant Recipients

Norovirus is a leading cause of diarrhea in transplant recipients. Norovirus can cause a severe acute syndrome in this patient population. Transplant recipients can also develop a chronic diarrheal syndrome with associated frailty, prolonged viral shedding, hospitalizations, and rejection, with associated mortality. Despite the significant burden of disease and improved diagnostics, there are no specific treatments to target norovirus. We aim to review the virology, epidemiology, diagnosis, clinical presentation, management, and prevention of norovirus. A recent retrospective observational study included nine solid organ transplant recipients (5 kidneys, 2 kidney-pancreas, 1 heart, and 1 lung) with chronic norovirus (median duration of diarrhea 12 weeks). Six of these nine patients demonstrated resolution of diarrhea at hospital discharge after oral human immune globulin. A recent phase II randomized controlled trial including solid organ transplant and bone marrow transplant recipients with norovirus compared nitazoxanide with placebo. Nitazoxanide did not demonstrate improved time to resolution of symptoms or duration of viral shedding but may have resulted in transient symptom improvement. Norovirus causes significant morbidity and mortality in transplant recipients. Although there are no approved treatment options, there are multiple strategies available, including supportive care, reduction in immunosuppression, intravenous immunoglobulin (IVIG), oral human immune globulin (OHIG), vitamin A, ribavirin, nitazoxanide, and the use of mammalian target of rapamycin (mTOR) inhibitors. Randomized controlled trials are needed to better study these strategies and prevention through the development of a universally available vaccine.