'World Health Organization, Western Pacific Regional Office'
Abstract
Objective: To assess the magnitude and severity of the 2012 influenza season in Victoria, Australia using surveillance data
from five sources.
Methods: Data from influenza notifications, sentinel general practices, a sentinel hospital network, a sentinel locum service
and strain typing databases for 2012 were descriptively analysed.
Results: Influenza and influenza-like illness activity was moderate compared to previous years, although a considerable
increase in notified laboratory-confirmed influenza was observed. Type A influenza comprised between 83% and 87%
of cases from the general practitioners, hospitals and notifiable surveillance data. Influenza A/H3 was dominant in
July and August, and most tested isolates were antigenically similar to the A/Perth/16/2009 virus used in the vaccine.
There was a smaller peak of influenza type B in September. No tested viruses were resistant to any neuraminidase inhibitor
antivirals. Higher proportions of type A/H3, hospitalized cases and those with a comorbid condition indicated for influenza
vaccination were aged 65 years or older. Influenza vaccination coverage among influenza-like illness patients was 24% in
sentinel general practices and 50% in hospitals.
Discussion: The 2012 influenza season in Victoria was average compared to previous years, with an increased dominance
of A/H3 accompanied by increases in older and hospitalized cases. Differences in magnitude and the epidemiological
profile of cases detected by the different data sources demonstrate the importance of using a range of surveillance data to
assess the relative severity of influenza seasons.VIDRL receives support for its influenza surveillance programme from the Victorian Government Department of Health. The Melbourne WHO Collaborating Centre for Reference and Research on Influenza is supported by the Australian Government Department of Health and Ageing. FluCAN is supported by the Department of Health and Ageing