Epidemiological and virological characteristics of seasonal influenza in the Western Pacific Region of the World Health Organization, 2011–2015
DOI:
https://doi.org/10.5365/wpsar.2017.8.1.004Abstract
Seasonal influenza causes yearly epidemics throughout the world and is a major cause of morbidity and mortality. Influenza surveillance systems have been in place throughout the Western Pacific Region of the World Health Organization for many years and continue to evolve. The virological and epidemiological data reported to WHO from this region were examined for the period 2011 to 2015 and compared with data from a prior summary from 2006 to 2010. Reporting increased substantially, approximately 10-fold, between 2006 and 2015, particularly following the 2009 A(H1N1)pdm09 pandemic. Data were aggregated into four zones based on geographic location and exhibited seasonal trends. Analyses of the data showed seasonal trends and periods of heightened influenza activity in the northern temperate zone, China, and the southern zone. There were no clear seasonal trends in the tropical zone. Collection and analysis of influenza surveillance data are important to guide influenza vaccination policy and recommendations, especially regarding viral subtypes to be included in vaccines and identification of groups that are at particularly high risk of influenza infections. Additionally, these data allow for a comprehensive overview of seasonal influenza in the region and evaluate how surveillance systems in the region have evolved.
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