Rolling up sleeves in the war on bird flu

By Stephen Cauchi
Science Reporter

October 24, 2005
Dose of prevention: Aemilia Gallo receives a shot of the trial vaccine at the Royal Children's Hospital.

Photo: Wayne Taylor

IF AND when bird flu strikes Australia, Aemilia Gallo can be satisfied knowing she has played her part to stop it.

Ms Gallo, of Moonee Ponds, is one of 400 Australian volunteers, half of them from Melbourne, taking part in a trial for bird flu vaccine — a vaccine that may save the lives of millions.

"My brother did the papilloma trial last year so we got contacted and I decided it was something that I'd do," she said. "I just thought it was a really worthwhile experience. It's also something that's going to benefit other people as well. You hear about it all the time, that it's out there."

There are a few downsides, of course, including several sharp needles. Ms Gallo received her first injection of the vaccine on Friday and will get another in three weeks. Then there's blood tests to see how her body has reacted.

The problem with vaccines is their side effects, which in some cases can be very severe. "I'm expecting just the common symptoms: redness, swelling around the area, maybe a version of the flu. Then there's the rarer side effects: neurological changes and things like that. But they're very, very rare."

The vaccine, being developed by CSL with help from the Murdoch Children's Research Institute, is designed to prevent people getting bird flu in the first place. If people are unfortunate enough to contract it, Tamiflu and Relenza are the only drugs available to treat it.

The strain used in the trial was taken from a bird flu victim in Vietnam and neutralised to prevent it from being contagious.

Humans can catch bird flu only from birds, especially chickens. So lethal is this current form of bird flu — known as H5N1 — that half of its 120 or so human victims have died.

Scientists are worried that the deadly virus will change to a form where people can easily catch it from other people, such as regular flu. This would accelerate the spread of bird flu among humans worldwide.

But there are many forms this human-to-human virus may take, even if derived from the same H5N1 strain.

"There's no guarantees that this (vaccine) will work. That's why the studies are being done," said Terry Nolan, head of the Murdoch's vaccine and immunisation research group.

"If this candidate doesn't work, and it's back to the drawing board, who knows how long it will take."

Dr Nolan said that if the vaccine was successful, it could be fine-tuned within several weeks to make it even more effective. But the vaccine needed to be successful in the first place.

"The change in the virus structure will determine the extent to which the vaccine that's being developed at the moment will be suitable," he said.

Dr Nolan said a human-to-human form of the virus was inevitable. "The mutation that's required is not a major mutation. It's quite an easy, simple change in the genetic sequence that will give it the ability to bind more easily to the human cell receptors. It's inevitable that it will occur — but when, nobody is saying."

The vaccine trial involves four different dosages, involving two of 7.5 micrograms and two of 15 micrograms. One of each dose has an adjuvant (a chemical to make it more potent). CSL will try to determine which of the four works best.

If all of Australia's 20 million people need the vaccine — which will probably require two shots per person — CSL says it can fill the order in three months.
