Influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza annual report, 2014

The WHO Collaborating Centre for Reference and Research on Influenza in Melbourne is part of the World Health Organization's (WHO) Global Influenza Surveillance and Response System. In 2014 the Centre received a total of 5,374 influenza samples from laboratories primarily in the Asia-Pacific region. Viruses were characterised by their antigenic, genetic and antiviral drug resistance properties. Of the viruses successfully analysed 52% were A(H1N1)pdm09 viruses. The majority of these were antigenically and genetically similar to the WHO recommended reference strain for the 2014 Southern Hemisphere influenza vaccine. Results for A(H3N2) and B/Yamagata viruses suggested that circulating viruses of this subtype and lineage, respectively, had undergone antigenic and/or genetic changes, consistent with the decision by WHO to change recommended strains for the 2015 Southern Hemisphere vaccine. A small number of A(H1N1)pdm09 and B/Victoria viruses had highly reduced inhibition to the neuraminidase inhibitors oseltamivir and zanamivir. The Centre also undertook primary isolation of vaccine candidate viruses directly into eggs. A total of 38 viruses were successfully isolated in eggs, of which 1 (B/Phuket/3073/2013) was included in the 2015 Southern Hemisphere influenza vaccine.