Figure 1: High activity of norovirus GII.17 during the 2014–2015 winter in Hong Kong.

(a) Temporal distribution of hospitalized norovirus GII.4 and GII.17 cases during the study period from March 2014 to May 2015. Black arrow denotes first detection (27 September 2014) of the novel GII.17 Kawasaki 2014. (b) Age distribution of norovirus GII.4 (n=163) and GII.17 (n=128) cases. Red horizontal lines and purple rectangular shades indicate medians and interquartile ranges, respectively. ****P<0.0001 (Mann–Whitney U-test).