Fig. 1From: Phylogenetic analysis and clinical characteristics of the co-occurring mutations in HA and NA genes of influenza A(H1N1)pdm09 viruses during 2015–2017 in Beijing, ChinaDistribution of influenza viruses in northern China. The data were from weekly data of Influenza Laboratory Surveillance Network during April 2015 to May 2017. Red is A(H1N1)pdm09, green is influenza H3N2, and blue is influenza BBack to article page