Initial findings from Australia's swine flu
vaccine trial reveal that it's effective with
just one dose and safe for adults.
Image: iStockphoto

The first results of the Australian swine flu vaccine trial, created by CSL, have revealed that the vaccine is successful with just one dose.

“The study showed that a very high percentage of the adult recipients produced a good antibody response, which should provide a high level of protection, to a single dose of vaccine," said Dr Alan Hampson, chair of the Australian Influenza Specialist Group.

The CSL vaccine against H1N1 was tested on 240 healthy adults aged 18 to 64 years old.

An immune response was seen after just a single 15mcg dose of the vaccine, which means supplies will go a lot further than though.

Each participant received an initial vaccination followed by a second three weeks later. The trial tested both 15mcg and 30mcg doses and blood samples were taken three weeks after each dose.

The 15mcg dose resulted in 96.7 per cent of participants having a strong antibody response, while the 30mcg dose result in 93.3 per cent of participants being protected.

"This is great news as it means that available vaccine supplies will go much further than might have been anticipated and that protection can be achieved with a type of vaccine that has a long history of safe and effective use," said Dr Hampson.

The trial revealed that the vaccine is safe in adults. Side effects were similar to those of the seasonal influenza vaccines.

“It is important too that the safety profile is good. Results in children are keenly awaited,” said Professor Robert Booy, from the National Centre for Immunisation Research & Surveillance.

The research has important implications for the future of pandemic influenza control.

"The data also suggests that previous experience with viruses of the same subtype, even though quite distantly related as in the case of the current H1N1 outbreak, can prime the immune response so that a single dose of a pandemic vaccine can be effective.  This may have important implications for the way that we might be able to respond to future, potentially far more severe, influenza pandemics,” said Dr Hampson.

The study is being published online in the New England Journal of Medicine.