Fig. 3.

Positive rates of different lineages in recent influenza seasons in Chinese mainland.

The positive rates of subtype H3N2, H1N1 and lineage B during the 2019–2020 (A), 2018–2019 (B), 2017–2018 (C) and 2016–2017 (D) influenza seasons are shown with blue, red and green lines, respectively. Meanwhile, the positive rates for Southern China and Northern China are shown with dashed lines and dotted lines, respectively. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)