Caini, SaverioHuang, Q. SueCiblak, Meral A.Kusznierz, GabrielaOwen, RhondaWangchuk, SonamHenriques, Claudio Maierovitch PessanhaNjouom, RichardFasce, Rodrigo A.Yu, HongjieFeng, LuzhaoZambon, MariaClara, Alexey W.Kosasih, HermanPuzelli, SimonaKadjo, HerveEmukule, GideonHeraud, Jean-MichelWei Ang, LiVenter, MarietjieMironenko, AllaBrammer, LynnetteMai, Le Thi QuynhSchellevis, FrançoisPlotkin, StanleyPaget, John2015-11-042015-11-042015Caini, S, Huang, QS, Ciblak, MA, Kusznierz, G, Owen, R et al. 2015, 'Epidemiological and virological characteristics of influenza B: results of the Global Influenza B Study', Influenza and Other Respiratory Viruses, vol. 9, suppl. 1, pp. 3–12.1750-2640 (print)1750-2659 (online)10.1111/irv.12319http://hdl.handle.net/2263/50318INTRODUCTION Literature on influenza focuses on influenza A, despite influenza B having a large public health impact. The Global Influenza B Study aims to collect information on global epidemiology and burden of disease of influenza B since 2000. METHODS Twenty-six countries in the Southern (n = 5) and Northern (n = 7) hemispheres and intertropical belt (n = 14) provided virological and epidemiological data. We calculated the proportion of influenza cases due to type B and Victoria and Yamagata lineages in each country and season; tested the correlation between proportion of influenza B and maximum weekly influenzalike illness (ILI) rate during the same season; determined the frequency of vaccine mismatches; and described the age distribution of cases by virus type. RESULTS The database included 935 673 influenza cases (2000– 2013). Overall median proportion of influenza B was 22 6%, with no statistically significant differences across seasons. During seasons where influenza B was dominant or co-circulated (>20% of total detections), Victoria and Yamagata lineages predominated during 64% and 36% of seasons, respectively, and a vaccine mismatch was observed in 25% of seasons. Proportion of influenza B was inversely correlated with maximum ILI rate in the same season in the Northern and (with borderline significance) Southern hemispheres. Patients infected with influenza B were usually younger (5–17 years) than patients infected with influenza A. CONCLUSION Influenza B is a common disease with some epidemiological differences from influenza A. This should be considered when optimizing control/prevention strategies in different regions and reducing the global burden of disease due to influenza.en© 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License,Burden of diseaseEpidemiologyGlobal Influenza B Study (GIBS)InfluenzaVaccinationVaccine mismatchArticle