Minimally invasive saliva testing to monitor norovirus infection in community settings

Background. Norovirus is a leading cause of acute gastroenteritis worldwide. Routine norovirus diagnosis requires stool collection. Te goal of this study was to develop and validate a noninvasive method to diagnose norovirus to complement stool diagnostics and to facilitate studies on transmission. Methods. A multiplex immunoassay to measure salivary immunoglobulin G (IgG) responses to 5 common norovirus genotypes (GI.1, GII.2, GII.4, GII.6, and GII.17) was developed. Te assay was validated using acute and convalescent saliva samples collected from Peruvian children <5 years of age with polymerase chain reaction (PCR)-diagnosed norovirus infections (n = 175) and controls (n = 32). Te assay sensitivity and specifcity were calculated to determine infection status based on fold rise of salivary norovirus genotype-specifc IgG using norovirus genotype from stool as reference. Results. Te salivary assay detected recent norovirus infections and correctly assigned the infecting genotype. Sensitivity was 71% and specifcity was 96% across the evaluated genotypes compared to PCR-diagnosed norovirus infection. Conclusions. Tis saliva-based assay will be a useful tool to monitor norovirus transmission in high-risk settings such as daycare centers or hospitals. Cross-reactivity is limited between the tested genotypes, which represent the most commonly circulating genotypes.