An Australian pharmaceutical company will begin trials Wednesday of its experimental swine flu vaccine.

CSL Ltd. will test the vaccine on 240 volunteers between the ages of 18 and 64 starting at Royal Adelaide Hospital in Australia's south, the company and media reports said.

The trial will involve participants receiving two injections of the vaccine, three weeks apart, and will compare a standard dosage with an increased dosage. Doctors will be looking to find at what dose volunteers develop an appropriate immune response.

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"We appreciate that new influenza strains like the swine flu can surprise us with properties that mean they might require higher dosing and two injections rather than one to provoke the desired level of immune response in humans," Dr. Russell Basser, the company's global director of clinical development, said in a statement.

Dr. Rachel David, speaking for the company, said 400 children will also be involved in the vaccine trial.

"We're talking about kids aged between 6 months and 9 years and it involves two injections and two blood tests, so four needles to monitor the results," she was quoted as saying by Australia's ABC News.

"I think that is a big commitment for families but in spite of that we've had a number of people come forward because they're interested in not getting the flu," she said.

The World Health Organization said Tuesday that there have been more than 700 deaths from swine flu since the start of the outbreak. The figure is an increase of some 300 since the start of the month.