Fig. 2From: Increasing serum antibodies against type B influenza virus in 2017–2018 winter in Beijing, ChinaComparison of HI titer distributions against two lineages of Flu B viruses by Spearman tests. We can see categories of HI titer to both lineages increased significantly in 2017–2018 than in 2016–2017. Moderate correlation can be found between B/Y and B/V lineage as the HI titers in 2016–2017 (a) and 2017–2018 (b)Back to article page