Answers are grounded in this paper and cite their sources.
Forty-nine influenza B virus isolates collected in Belgium, Finland, Spain, and Israel during the 2001-2002 winter season were categorized into either of two lineages, B/Yamagata/16/88 or B/Victoria/2/87, based on the phylogenetic studies of HA1 sequences. The data trace the geographic spread of B/Victoria/2/87-like viruses and support the emergence of B/Hong Kong/1351/02-like viruses, possibly due to selective advantages of reassortment.
No takes yet. Share an insight, caveat, or question.
Chi et al. (2003) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: