Caini, SaverioSpreeuwenberg, PeterKusznierz, Gabriela F.Rudi, Juan ManuelOwen, RhondaPennington, KateWangchuk, SonamGyeltshen, SonamFerreira de Almeida, Walquiria AparecidaPessanha Henriques, Cláudio MaierovitchNjouom, RichardVernet, Marie-AstridFasce, Rodrigo A.Andrade, WinstonYu, HongjieFeng, LuzhaoYang, JuanPeng, ZhibinLara, JennyBruno, Alfredode Mora, Doménicade Lozano, CelinaZambon, MariaPebody, RichardCastillo, LeticiaClara, Alexey W.Matute, Maria LuisaKosasih, HermanNurhayati, nullPuzelli, SimonaRizzo, CaterinaKadjo, Herve ADaouda, CoulibalyKiyanbekova, LyazzatOspanova, AkerkeMott, Joshua A.Emukule, Gideon O.Heraud, Jean-MichelRazanajatovo, Norosoa HarlineBarakat, AmalEl Falaki, FatimaHuang, Sue Q.Lopez, LizaBalmaseda, AngelMoreno, BrechlaRodrigues, Ana PaulaGuiomar, RaquelAng, Li WeiLee, Vernon Jian MingVenter, MarietjieCohen, CherylBadur, SelimCiblak, Meral A.Mironenko, AllaHolubka, OlhaBresee, JosephBrammer, LynnetteHoang, Phuong Vu MaiLe, Mai Thi QuynhFleming, DouglasSéblain, Clotilde El-GuercheSchellevis, FrançoisPaget, JohnGlobal Influenza B Study group2019-03-202019-03-202018-06-08BMC Infect Dis. 2018 Jun 8;18(1):269. doi: 10.1186/s12879-018-3181-y1471-2334http://hdl.handle.net/10400.18/6252The Global Influenza B Study group also includes the following members: Binay Thapa 4 , Sangay Zangmo 4 , Guy Vernet 6 , Patricia Bustos 7 , Patricio Loyola 7 , Joanna Ellis 12, Antonino Bella 19, Maria Rita Castrucci 18, Gulzhan Muratbayeva 45, Julia Guillebaud 26, Laurence Randrianasolo 46, Ausenda Machado 47, Pedro Pechirra 32, Jeffery Cutter 34, Raymond Tzer Pin Lin 34. 45 Centers for Disease Control and Prevention, Central Asia Regional Office, Almaty, Kazakhstan 46 Epidemiology Unit, Institut Pasteur of Madagascar, Antananarivo, Madagascar 47 National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5994061/Background: Influenza disease burden varies by age and this has important public health implications. We compared the proportional distribution of different influenza virus types within age strata using surveillance data from twenty-nine countries during 1999-2014 (N=358,796 influenza cases). Methods: For each virus, we calculated a Relative Illness Ratio (defined as the ratio of the percentage of cases in an age group to the percentage of the country population in the same age group) for young children (0-4 years), older children (5-17 years), young adults (18-39 years), older adults (40-64 years), and the elderly (65+ years). We used random-effects meta-analysis models to obtain summary relative illness ratios (sRIRs), and conducted meta-regression and sub-group analyses to explore causes of between-estimates heterogeneity. Results: The influenza virus with highest sRIR was A(H1N1) for young children, B for older children, A(H1N1)pdm2009 for adults, and (A(H3N2) for the elderly. As expected, considering the diverse nature of the national surveillance datasets included in our analysis, between-estimates heterogeneity was high (I2>90%) for most sRIRs. The variations of countries’ geographic, demographic and economic characteristics and the proportion of outpatients among reported influenza cases explained only part of the heterogeneity, suggesting that multiple factors were at play. Conclusions: These results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.engInfluenzaAge DistributionInfluenza A VirusH3N2 SubtypeInfluenza A VirusH1N1 SubtypeInfluenza B VirusMeta-analysisEstados de Saúde e de Doençajournal article10.1186/s12879-018-3181-y