A South Australian man has become the 21st person in Australia to die with swine flu.
Health authorities said the 32-year-old died on Wednesday in the intensive care unit at the Lyell McEwin Hospital in Adelaide's north.
He had been transferred there from Modbury Hospital late last week.
SA chief medical officer Paddy Phillips said the man had chronic underlying health issues.
"And I understand that has been the same for all of the people who have died around the country," he told reporters on Wednesday.
"This remains a mild illness in the vast majority of people.
"At this stage we are not going into any further details about the young man out of respect for his family."
Professor Phillips said South Australia had been selected as the first state to trial the H1N1 vaccine.
"It's great for SA ... it will help us understand the effectiveness and the dose that is necessary and I'm optimistic that CSL will be able to get the vaccine out into the community as soon as possible," he said.
There are currently 12 people in hospital with swine flu across SA, including one who remains in intensive care but in a stable condition.
It is understood the number of people suffering from swine flu across the state has increased dramatically in the past few days.
"What we are seeing here and around Australia is that as more people do become infected there will be more people who become hospitalised as a proportion," Professor Phillips said.
"Prevention is still better than cure."
Of the 1,162 people who have tested positive for swine flu across SA, the man who died on Wednesday morning is the second person to die with the H1N1 virus in the state.
The first was an Aboriginal man from Western Australia, who died at the Royal Adelaide Hospital last month after being transferred from the Alice Springs Hospital with a number of other serious medical conditions.
The Aboriginal man was the first person in Australia to die with the virus.
Meanwhile, a 38-year-old Queensland woman became Australia's 22nd person with swine flu to die.