Table 3.

HI antigenic analyses of influenza B viruses (Victoria-lineage).

Reference B/Victoria-lineage viruses	Genetic group	Passage history	No of isolates	Reduction in HI titre compared to homologous titre
				≤ 2-fold	4-fold	≥ 8-fold
B/Malaysia/2506/2004	1A	E3/E7	19	–	–	19
B/Brisbane/60/2008	1A	E4/E4	19	–	–	19
B/Malta/636714/2011	1A	E4/E1	19	–	–	19
B/South Australia/81/2012	1A	E4/E2	19	–	–	19
B/Johannesburg/3964/2012	1A	E1/E2	19	–	–	19
B/Formosa/V2367/2012	1A	MDCK1/MDCK3	19	7	12	–
B/Hong Kong/514/2009	1B	MDCK1/MDCK1	19	19	–	–
B/Ireland/3154/2016	1A	MDCK3	19	19	–	–
B/Nordrhein-Westfalen/1/2016	1A	C2/MDCK1	19	19	–	–

E — egg isolate.