Epidemiology of influenza B in Australia: 2001‐2014 influenza seasons. Issue 2 (14th October 2016)

• Record Type: Journal Article
• Authors: Moa, Aye M.; Muscatello, David J.; Turner, Robin M.; MacIntyre, Chandini R.
• Is Part Of: Influenza and other respiratory viruses. Volume 11:Issue 2(2017)
• Page Start: 102
• Page End: 109
• Publication Date: 2016-10-14
• Subjects: Australia -- epidemiology -- influenza B -- Victoria lineage -- Yamagata lineage; Influenza -- Periodicals; Respiratory infections -- Periodicals; Virus diseases -- Periodicals; Influenza, Human -- Periodicals; Respiratory Tract Diseases -- Periodicals; Virus Diseases -- Periodicals; Grippe -- Périodiques; Appareil respiratoire -- Infections -- Périodiques; Maladies à virus -- Périodiques; 616.203
• DOI: 10.1111/irv.12432
• Languages: English
• ISSNs: 1750-2640

Abstract

Abstract : 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.