Risk Factors for Norovirus Gastroenteritis among Nicaraguan Children.

Norovirus is a leading cause of pediatric gastroenteritis. Understanding norovirus epidemiology is essential for reducing disease burden. We conducted a case-control study to describe the distribution, clinical features, and risk factors of norovirus gastroenteritis among children < 5 years of age in León, Nicaragua. Cases were children testing positive for norovirus and controls were children living in the cases' communities. Study staff interviewed mothers of enrolled cases and controls to obtain detailed exposure information including food, water, and sanitation sources; recent exposures; household characteristics; and handwashing practices. In addition, study staff requested stool samples to be tested for norovirus from select household members. We used descriptive statistics to understand the epidemiologic and clinical features of gastroenteritis episodes. To analyze potential risk factors, we used Firth's penalized logistic regression to estimate crude and adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs). There were 102 children with gastroenteritis, 18 cases of norovirus and 31 controls. Norovirus cases occurred later in the year, corresponding to a delay in the rainy season. Cases were more likely to have a household member with norovirus in their stool as compared with controls [crude OR: 13.3 (95% CI: 2.5, 136.2) and adjusted OR: 11.5 (95% CI: 1.6, 223.2)]. In addition, alcohol-based hand sanitizer use among household members was reported for 10 (32%) of controls and but never for cases. Further research is needed to understand household transmission of norovirus in low- and middle-income countries and the potential impact of hand sanitizer use.