Figure 2 shows in solid lines the onset of illness across the course of each season (2010-14) for patients aged 18-64 years who were hospitalised with influenza - most patients were admitted after the beginning of June (week 22). The majority of the cumulative proportion of vaccinated Flutracking respondents aged 18-64 years who reported being vaccinated across each season, were vaccinated before large numbers of hospitalised patients in the same age group were becoming unwell from influenza infection.