Norovirus Detection in Water Samples: A Systematic Review and Meta-Analysis of Global Evidence, Methodological Heterogeneity, and Surveillance Readiness

Norovirus water monitoring may complement clinical and water-safety surveillance, but the readiness of the available evidence for routine public-health use remains unclear. We assessed the global distribution, detection patterns, methodological heterogeneity, reporting completeness, and public-health translation of molecular norovirus detection in water. We searched PubMed, Web of Science, the Cochrane Library, Scopus, CNKI, and Wanfang Data from database inception to June 2025. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance, we identified 90 eligible studies. We mapped geographic and water-system coverage, synthesized reported norovirus genogroup I/II (GI/GII) positivity using random-effects models, and evaluated methodological heterogeneity, reporting completeness, public-health linkage, and surveillance readiness. Evidence was reported from 31 countries; 87 studies were geographically mappable, yielding 92 article-country placements. Across 51 strata from 36 studies, random-effects reported a global norovirus positivity rate of 62% (95% confidence interval [CI]: 45–77%) in wastewater and 5% (95% CI: 2–17%) in groundwater; heterogeneity was substantial. In exploratory meta-regression, multi-virus assays had lower reported positivity than single-virus assays after adjustment for water type (odds ratio [OR] = 0.28; bias-reduced cluster-robust 95% CI: 0.11–0.67). Limit of detection, sensitivity, and specificity were reported by 31, 6, and 5 studies, respectively, and 3 studies reported all 3 metrics. Repeated sampling was used in 59 studies, of which 52 reported collection cadence. Twenty-nine studies linked water findings to epidemiological/community surveillance or outbreak investigation; 2 directly applied norovirus water testing in outbreak investigations, and none demonstrated prospective early warning. Five studies met the predefined full surveillance-ready reporting package. Molecular methods detected norovirus across diverse water-system contexts, but the evidence base was geographically concentrated, methodologically heterogeneous, and incompletely connected to operational public-health surveillance. Standardized sampling and analytical reporting, comparable quantitative outputs, and prospective linkage with public-health data are needed before routine implementation.