Antiviral drugs were being wasted on mild cases of the swine flu and the scenario could lead them being rendered ineffective against new strains of the virus in the future, experts have suggested.
The director of the Infectious Diseases Department at Victoria's Austin Health, Dr Lindsay Grayson, and deputy director Dr Paul Johnson have suggested authorities jumped the gun in encouraging widespread use of Tamiflu (oseltamivir) in cases of the swine flu – an outbreak that they claimed had "fallen well short of the worst-case scenario".
"To be effective, the drug should be commenced within 48 hours of disease onset," Dr Grayson and Dr Johnson wrote in the Medical Journal of Australia.
"With laboratory results taking days to return, the only clinical solution would be to commence oseltamivir immediately [when] influenza is suspected — in which case, at Austin Health we would be treating up to 80 per cent of patients for a disease they do not have.
"Already it is known that the main seasonal influenza strain in the United States in 2008 was resistant to oseltamivir. The real nightmare scenario will be if the current swine flu strain also develops resistance in the face of widespread use of oseltamivir, leaving us with few treatment options.
"We are currently wasting oseltamivir on a mild illness when we are likely to need it next year, when the current strain could become more aggressive."
With 2,118 reported cases of the virus in Australia, the Government yesterday changed its response to the outbreak into a newly-created 'protect' phase, which shifts focus onto treating severe cases.
Dr Grayson and Dr Johnson claimed the model used in the Australian Health Management Plan for Pandemic Influenza (AHMPPI ) was not suited for the swine flu virus and criticised authorities' front line response to the outbreak.
"Drug and mask distribution has been extremely slow, especially to general practitioners, who are crucial to effective disease management and containment," they wrote.
"Instead of being flexible and responding to feedback from the medical front line in Victoria, the AHMPPI has continued to be rigidly based on past assumptions. The process has tended to focus on managing data and information flow, rather than managing the sick patients."
The nation's chief medical officer Professor Jim Bishop, however, defended the Government's response, claiming the early use of Tamiflu helped reduce the spread of disease.
"As far as resistance is concerned, resistance to these antivirals has come via major genetic reassortment," Prof Bishop told the ABC.
"In the past it hasn't been the pressure of drugs but we also are concerned about that going forward. That's why that new phase is carefully adjusted to only take into account those who need it."