Distribution of influenza virus types by age using case-based global surveillance data from twenty-nine countries, 1999-2014
Creators: name: Caini, Saverio
name: Spreeuwenberg, Peter
name: Kusznierz, Gabriela F.
name: Rudi, Juan Manuel
name: Owen, Rhonda
name: Pennington, Kate
name: Wangchuk, Sonam
name: Gyeltshen, Sonam
name: de Almeida, Walquiria Aparecida Ferreira
name: Henriques, Cláudio Maierovitch Pessanha
name: Njouom, Richard
name: Vernet, Marie-Astrid
name: Fasce, Rodrigo A.
name: Andrade, Winston
name: Yu, Hongjie
name: Feng, Luzhao
name: Yang, Juan
name: Peng, Zhibin
name: Lara, Jenny
name: Bruno, Alfredo
name: Mora, Doménica de
name: Lozano, Celina de
name: Zambon, Maria
name: Pebody, Richard
name: Castillo, Leticia
name: Clara, Alexey W.
name: Matute, Maria Luisa
name: Kosasih, Herman
name: Nurhayati
name: Puzelli, Simona
name: Rizzo, Caterina
name: Kadjo, Herve A.
name: Daouda, Coulibaly
name: Kiyanbekova, Lyazzat
name: Ospanova, Akerke
name: Mott, Joshua A.
name: Emukule, Gideon O.
name: Heraud, Jean-Michel
name: Razanajatovo, Norosoa Harline
name: Barakat, Amal
name: el Falaki, Fatima
name: Huang, Qiu Sue
name: Lopez, Liza
name: Balmaseda, Angel
name: Moreno, Brechla
name: Rodrigues, Ana Paula
name: Guiomar, Raquel
name: Ang, Li Wei
name: Lee, Vernon Jian Ming
name: Venter, Marietjie
name: Cohen, Cheryl
name: Badur, Selim
name: Ciblak, Meral A.
name: Mironenko, Alla
name: Holubka, Olha
name: Bresee, Joseph
name: Brammer, Lynnette
name: Hoang, Phuong Vu Mai
name: Le, Mai Thi Quynh
name: Fleming, Douglas
name: Séblain, Clotilde El-Guerche
name: Schellevis, François
name: Paget, John
name: group, Global Influenza B Study
Publisher: name: Institute of Environmental Science and Research
Year: 2019
Subjects: classificationCode: 420299
subject: Epidemiology not elsewhere classified
classificationCode: 420310
subject: Health surveillance
classificationCode: 420306
subject: Health care administration

description: <b>Background: </b>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). <br><b>Methods:</b> 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 metaregression and sub-group analyses to explore causes of between-estimates heterogeneity. <br><b>Results:</b> 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 (I-2&gt;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. <br><b>Conclusions:</b> These results highlight the importance of presenting burden of disease estimates by age group and virus (sub) type.