Influenza cases soar this season with mix of strains
20 May 2011
Laboratory-confirmed influenza cases have surged to more than 5 times the level seen in autumn last year, as the virus comes back with "a vengeance", an expert says.
National Notifiable Diseases Surveillance System data for May shows 8339 confirmed cases so far this year in Australia, up from 1637 in early 2010, although they're mostly confined to Queensland and the Northern Territory.
"It’s not widespread, but certainly there is a lot more [influenza] activity, especially in those states," said Dr Ian Barr, deputy director of the WHO Collaborating Centre for Reference and Research on Influenza.
"To see those cases at higher levels earlier in the year does maybe indicate that we are going to have a more severe year than last year, which was relatively mild."
Dr Barr said the pandemic H1N1 (swine flu) strain was the dominant influenza strain in 2010, though its impact was dulled by increased immunity, a hangover from its wide circulation and vaccination efforts during 2009.
A jump in lab-confirmed cases of flu caused by the H3N2 strain this year foreshadowed a return to a "mixture" of seasonal flu strains rather than the pandemic flu dominating again.
"This year we may see more of the traditional make-up of H3 viruses coming back with a bit of a vengeance," he said, adding cases were not severe.
Last Reviewed: 20 May 2011
