Jun 3, 2009 (CIDRAP News) Australian health officials acknowledged today that the novel H1N1 influenza virus has achieved sustained community transmission in the state of Victoria, where 521 cases were reported today, an increase of 126 since yesterday.
The Australia Department of Health and Ageing said the pandemic response for Victoria has been raised from "contain" to "sustain." The resulting measures "will enable Victoria to more appropriately respond to the relatively higher number of cases and the sustained community transmission of the infection in Victoria," the agency said in a statement.
Australia's overall novel H1N1 case count reached 633 today, with all eight states and territories reporting cases. In addition to Victoria's cases, New South Wales has reported 70, and Queensland has reported 26. For the remaining states and the two territories, case numbers are in the single digits.
The spread of the virus in Victoria suggests that the World Health Organization's (WHO's) formal criterion for a full-fledged pandemic (pandemic alert phase 6)sustained community transmission in more than one global regionhas probably been met.
The WHO has been holding off on a pandemic declaration because of concern that it may trigger undue alarm, given that the illness is mild in most cases. This week the agency said it would come up with a way to rate the disease's severity and provide related guidance in an effort to reduce undue alarm from a pandemic declaration.
Victoria's health minister, Daniel Andrews, said in a statement today that the state's move to a modified sustain phase of its influenza plan is being done to focus on protecting vulnerable people from the virus rather than containing the virus. Vulnerable groups include seniors, students at special development schools, hospital patients, and those who have chronic illnesses.
"The decision to move to a modified sustain phase of our plan acknowledges that Victoria's response to the H1N1 influenza virus is proportionate to the risk to the community," Andrews said.
The state will provide antiviral treatment only to those who have novel flu infections and their household contacts, require people with confirmed cases to isolate themselves for 3 days after starting treatment, conduct intensive surveillance in high-risk settings such as nursing homes, and enhance community surveillance for illnesses and changes in the circulating influenza strains.
Schools will no longer automatically close if a student has a flu-like illness, though large numbers of confirmed cases in a school might warrant closure.
Raina MacIntyre, professor of infectious diseases and epidemiology at the University of New South Wales in Sydney, told CIDRAP News that Victoria is the only state where sustained community transmission appears to be occurring. More than 75% of cases have occurred in children aged 5 to 18, she said.
The normal influenza season in Australia and the rest of the southern hemisphere is just getting under way, and global health officials worry that the novel flu virus could change when it circulates alongside the seasonal strains. Though weekly reports on Australia's flu season haven't yet begun, MacIntyre said so far labs are reporting that both seasonal and flu viruses are circulating.
At a news briefing yesterday, Dr. Keiji Fukuda of the WHO described Australia as one of several countries that seemed to be in transition between having scattered travel-related and institutional H1N1 cases and having sustained community transmission. He said the WHO had not yet seen evidence of "really widespread community transmission" in those countries.