Figure 1. Emergence of a new recombinant norovirus GII.P16-GII.2, Hong Kong, China, winter 2016–2017. A) Distribution of norovirus genotypes, July 2016–February 2017. B) Proportion of norovirus case-patients among 3 stratified age groups. C) Age distribution of hospitalized case-patients with GII.4 and GII.2 infections. A total of 214 GII.4 and 86 GII.2 case-patients are shown. Black horizontal lines represent medians. Gray shading denotes young adults (YA; 18–40 years of age). p value calculated by using Mann-Whitney U-test.