Fig. 2

Comparison of the norovirus model to A data from Harris et al. of age-specific incidence of symptomatic norovirus infection where this fit was used to estimate the probability of transmission given a contact, B weekly reported cases of norovirus reported to the SGSS system (thick brown line—5 year average, thin brown lines—minimum and maximum). The model incidence (per 100,000 person-years) was extrapolated to a national level, accounting for known under-reporting and under-ascertainment inherent in the surveillance data (287.6 (95%CI 239.1–346.0)) and a further 27% reduction in incidence in the model for alignment with the reported data. Dashed lines indicate the first day of each calendar month. SGSS Second Generation Surveillance System