Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

• Published in: PloS one Vol. 11; no. 3; p. e0152310
• Main Authors: Caini, Saverio, Andrade, Winston, Badur, Selim, Balmaseda, Angel, Barakat, Amal, Bella, Antonino, Bimohuen, Abderrahman, Brammer, Lynnette, Bresee, Joseph, Bruno, Alfredo, Castillo, Leticia, Ciblak, Meral A, Clara, Alexey W, Cohen, Cheryl, Cutter, Jeffery, Daouda, Coulibaly, de Lozano, Celina, De Mora, Domenica, Dorji, Kunzang, Emukule, Gideon O, Fasce, Rodrigo A, Feng, Luzhao, Ferreira de Almeida, Walquiria Aparecida, Guiomar, Raquel, Heraud, Jean-Michel, Holubka, Olha, Huang, Q Sue, Kadjo, Herve A, Kiyanbekova, Lyazzat, Kosasih, Herman, Kusznierz, Gabriela, Lara, Jenny, Li, Ming, Lopez, Liza, Mai Hoang, Phuong Vu, Pessanha Henriques, Cláudio Maierovitch, Matute, Maria Luisa, Mironenko, Alla, Moreno, Brechla, Mott, Joshua A, Njouom, Richard, Nurhayati, Ospanova, Akerke, Owen, Rhonda, Pebody, Richard, Pennington, Kate, Puzelli, Simona, Quynh Le, Mai Thi, Razanajatovo, Norosoa Harline, Rodrigues, Ana, Rudi, Juan Manuel, Tzer Pin Lin, Raymond, Venter, Marietjie, Vernet, Marie-Astrid, Wangchuk, Sonam, Yang, Juan, Yu, Hongjie, Zambon, Maria, Schellevis, François, Paget, John
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 31-03-2016; Public Library of Science (PLoS)
• Subjects: Analysis; Biochemistry, Molecular Biology; Biology and life sciences; Care and treatment; Data processing; Disease control; Disease prevention; Earth sciences; Emerging diseases; Environmental science; Epidemics; Epidemiology; Health services; Health surveillance; Hemispheres; Human health and pathology; Humans; Immunization; Infectious diseases; Influenza; Influenza A; Influenza A virus; Influenza A virus - immunology; Influenza B; Influenza B virus; Influenza B virus - immunology; Influenza vaccines; Influenza, Human; Influenza, Human - epidemiology; Influenza, Human - prevention & control; Laboratories; Life Sciences; Management; Medical research; Medicine and Health Sciences; Microbiology and Parasitology; Molecular biology; Online databases; People and places; Prevention; Public health; Respiratory diseases; Retrospective Studies; Santé publique et épidémiologie; Seasonal variations; Seasons; Surveillance; Surveillance systems; Tropical Climate; Tropical environments; Vaccination; Virology; Viruses; Atlanta Georgia; Cameroon; Madagascar; Kazakhstan; Costa Rica; Netherlands; El Salvador; Morocco; China; Guatemala; Brazil; Chile; Ecuador; Istanbul Turkey; Argentina; Bhutan; United States > US; Kenya; New Zealand; Jakarta Indonesia; Beijing China; Nicaragua; Turkey; Italy; Honduras; Australia; Indonesia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0152310

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 vaccination programmes.
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 influenza epidemics.
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.