Fig. 1
From: Increasing serum antibodies against type B influenza virus in 2017–2018 winter in Beijing, China
Phylogenetic tree of the HA gene of type B influenza viruses used in the study. Phylogenic tree was constructed using the partial HA genes (370-610NT covering the most important positions distinguishing the Victoria and Yamagata lineages) from the clinic isolates and full-length HA sequences from the GenBank as well as GISAID. Strains labeled with black triangle represented as B/Victoria and B/Yamagata lineage viruses were used as antigens in the present study