Influenza vaccine strain selection and recent studies on the global migration of seasonal influenza viruses

Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
Vaccine (Impact Factor: 3.77). 09/2008; DOI: 10.1016/j.vaccine.2008.07.078
Source: PubMed


Annual influenza epidemics in humans affect 5–15% of the population, causing an estimated half million deaths worldwide per year [Stohr K. Influenza—WHO cares. Lancet Infectious Diseases 2002;2(9):517]. The virus can infect this proportion of people year after year because the virus has an extensive capacity to evolve and thus evade the immune response. For example, since the influenza A(H3N2) subtype entered the human population in 1968 the A(H3N2) component of the influenza vaccine has had to be updated almost 30 times to track the evolution of the viruses and remain effective. The World Health Organization Global Influenza Surveillance Network (WHO GISN) tracks and analyzes the evolution and epidemiology of influenza viruses for the primary purpose of vaccine strain selection and to improve the strain selection process through studies aimed at better understanding virus evolution and epidemiology. Here we give an overview of the strain selection process and outline recent investigations into the global migration of seasonal influenza viruses.

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    • "e grouped under B / Yam and B / Vic . Lineages . Others that were isolated before 1983 were not included in this classification . Numbers at each node of the tree show bootstrap percentages obtained after 1 , 000 replicates . been identified " East and Southeast Asian circulation network " as a leading migration route to Europe and North America [ Russell et al . , 2008 ] ."
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    • "As input, we are often given a set of aligned genetic sequences for which we wish to work out the pattern of ancestry. This analysis plays an important role in, for example, drug or vaccine development (McHardy & Adams, 2009; Russell et al., 2008). With the cost of sequencing decreasing rapidly due to next generation sequencing technologies (Metzker, 2010), more and more sequences are becoming available and deposited in sequence repositories such as GenBank (Benson et al., 2011). "
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