Table 3.
Summary of evolutionary and epidemiological characteristics of influenza B virus lineages
| Characteristics | Victoria | Yamagata |
|---|---|---|
| Age distribution | younger (mean 16.8, median 11) | older (mean 26.6, median 18) |
| Genetic diversity | strong seasonal changes | weak seasonal changes |
| R (medians) | higher (1.13–1.27) | lower (1.08–1.14) |
| Positive selection | stronger | weaker |
| Antigenic drift | relatively strong | relatively weak |
| Reassortment | high inter-sublineage reassortment, with lower intra-sublineage reassortment | low inter-sublineage reassortment, with greater intra-sublineage reassortment |
| Receptor binding preference | α-2,3- and α-2,6-linked sialic acid | mainly α-2,6 linked sialic acid |