Determining the optimal time to vaccinate is important for influenza vaccination programmes.
Here, we assessed the temporal characteristics of influenza epidemics in the
Northern and Southern hemispheres and in the tropics, and discuss their implications for
This was a retrospective analysis of surveillance data between 2000 and 2014 from the
Global Influenza B Study database. The seasonal peak of influenza was defined as the
week with the most reported cases (overall, A, and B) in the season. The duration of seasonal
activity was assessed using the maximum proportion of influenza cases during three
consecutive months and the minimum number of months with 80% of cases in the season.
We also assessed whether co-circulation of A and B virus types affected the duration of
212 influenza seasons and 571,907 cases were included from 30 countries. In tropical
countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B
coincided less frequently than in temperate countries. Temporal characteristics of influenza
epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than
influenza A seasons, especially in the tropics.
Our findings show that influenza seasonality is less well defined in the tropics than in temperate
regions. This has important implications for vaccination programmes in these countries.
High-quality influenza surveillance systems are needed in the tropics to enable
decisions about when to vaccinate.
Caini, Saverio; Spreeuwenberg, Peter; Kusznierz, Gabriela F.; Rudi, Juan Manuel; Owen, Rhonda; Pennington, Kate; Wangchuk, Sonam; Gyeltshen, Sonam; Ferreira de Almeida, Walquiria Aparecida; Henriques, Claudio Maierovitch Pessanha; Njouom, Richard; Vernet, Marie-Astrid; Fasce, Rodrigo A.; de Mora, Domenica; De Lozano, Celina; Zambon, Maria; Pebody, Richard; Castillo, Leticia; Clara, Alexey W.; Matute, Maria Luisa; Kosasih, Herman; Nurhayati; Puzelli, Simona; Rizzo, Caterina; Kadjo, Herve A.; Daouda, Coulibaly; Kiyanbekova, Lyazzat; Ospanova, Akerke; Mott, Joshua A.; Emukule, Gideon O.; Heraud, Jean-Michel; Razanajatovo, Norosoa Harline; Barakat, Amal; El Falaki, Fatima; Huang, Sue Q.; Lopez, Liza; Balmaseda, Angel; Moreno, Brechla; Rodrigues, Ana Paula; Guiomar, Raquel; Ang, Li Wei; Lee, Vernon Jian Ming; Venter, Marietjie; Cohen, Cheryl; Badur, Selim; Ciblak, Meral A.; Mironenko, Alla; Holubka, Olha; Bresee, Joseph; Brammer, Lynnette; Hoang, Phuong Vu Mai; Quynh Le, Mai Thi; Fleming, Douglas; Seblain, Clotilde El-Guerche; Schellevis, François; Paget, John; Global Influenza B Study group(BioMed Central, 2018-06-08)
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 ...
Ali, Abdel Hakim M.; Samy, Mohamed M.; Fasina, Folorunso Oludayo; Hassan, Mohamed K.; Kilany, Walid H.; El‑Mahdy, Souzan; Saad, Ahmed; Lubroth, Juan; Jobre, Yilma(Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, 2019-09-30)
Egypt has a large traditional and exotic poultry sector which is challenged regularly by poultry
diseases in endemic and epidemic proportions. The household poultry in particular is a
source of livelihoods and employment ...
Phylogenetic analyses of the complete genomes of the highly pathogenic avian influenza (HPAI) 188.8.131.52c H5N1 virus strains causing outbreaks in Nigeria's poultry population from 2014 to 2016 showed evidence of distinct ...