Open AccessEpidemiology of influenza B in Australia: 2001‐2014 influenza seasons
Author(s) -
Moa Aye M.,
Muscatello David J.,
Turner Robin M.,
MacIntyre Chandini R.
Publication year - 2017
Publication title -
influenza and other respiratory viruses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.743
H-Index - 57
eISSN - 1750-2659
pISSN - 1750-2640
DOI - 10.1111/irv.12432
Subject(s) - epidemiology , human mortality from h5n1 , incidence (geometry) , virology , influenzavirus b , lineage (genetic) , influenza season , influenza vaccine , medicine , biology , vaccination , influenza a virus , immunology , demography , orthomyxoviridae , virus , disease , covid-19 , genetics , infectious disease (medical specialty) , gene , physics , sociology , optics
Background Influenza B is characterised by two antigenic lineages: B/Victoria and B/Yamagata. These lineages circulate together with influenza A during influenza seasons, with varying incidence from year to year and by geographic region. Objective To determine the epidemiology of influenza B relative to influenza A in Australia. Methods Laboratory‐confirmed influenza notifications between 2001 and 2014 in Australia were obtained from the Australian National Notifiable Diseases Surveillance System. Results A total of 278 485 laboratory‐confirmed influenza cases were notified during the study period, comprising influenza A (82.2%), B (17.1%) and ‘other and untyped’ (0.7%). The proportion of notifications that were influenza B was highest in five‐ to nine‐year‐olds (27.5%) and lowest in persons aged 85 years and over (11.5%). Of all B notifications with lineage determined, 77.1% were B/Victoria and 22.9% were B/Yamagata infections. Mismatches between the dominant B lineage in a season and the trivalent vaccine B lineage occurred in over one‐third of seasons during the study years. In general, influenza B notifications peaked later than influenza A notifications. Conclusion The proportion of circulating influenza B in Australia during 2001‐2014 was slightly lower than the global average and was dominated by B/Victoria. Compared with influenza A, influenza B infection was more common among older children and young adults and less common in the very elderly. Influenza B lineage mismatch with the trivalent vaccine occurred about one‐third of the time.