An application of nowcasting methods: Cases of norovirus during the winter 2023/2024 in England

• DOI: 10.1371/journal.pcbi.1012849
• Publication Date: 2025-02-21T18:45:10Z
• Authors: Jonathon Mellor; Maria L. Tang; Emilie Finch; Rachel Christie; Oliver Polhill; Christopher E. Ov...; Ann Hoban; Amy Douglas; Sarah R. Deeny; Thomas Ward
• Keywords: Nowcasting

Background Norovirus is a leading cause of acute gastroenteritis, adding to strain on healthcare systems. Diagnostic test reporting norovirus often delayed, resulting in incomplete data for real-time surveillance. Methods To nowcast the case burden generalised additive model (GAM), semi-mechanistic Bayesian joint process and delay “epinowcast”, structural time series (BSTS) including syndromic surveillance were developed. These models evaluated over weekly nowcasts using probabilistic scoring framework. Results Using weighted interval score (WIS) we show heuristic approach outperformed by harnessing corrections, with daily mean WIS = 7.73, 3.03, 2.29 baseline, GAM, respectively. Forecasting approaches reliable event temporally changing values, 4.57 BSTS model. However, (111 online pathways) did not improve model, 10.28, potentially indicating poor correspondence between indicators. Interpretation Analysis enhanced nowcasting delayed improves understanding simple assumptions, important decision making. The modelling needs be informed patterns can have large impacts operational performance insights produced.