Figure 4. Model estimates of A) incidence of symptomatic norovirus infections by age and norovirus year, B) predictions of cases reported within SGSS for the 2021/2022 year, compared with a typical norovirus year.

Simulations assuming a duration of shedding of 15 days and no under-reporting (outcomes from other simulations are shown in “Additional file 5”). Dashed lines indicate the first day of each calendar month. SGSS: Second Generation Surveillance System.