Malaria vaccine 'close'

Roberta Mancuso | 13 Feb 2006
The Advertiser

Researchers at the Queensland Institute of Medical Research (QIMR) today announced they would begin testing for a new vaccine within a year after preliminary animal studies revealed it was possible to become immune to more than one of the four strains of malaria.

Malaria, a potentially deadly parasitic disease spread through the bite of particular types of mosquito, kills around two million people worldwide each year, or one person every 15 seconds.

Forty per cent of the global population is at risk.

Dr Michael Good, director of QIMR and head of the Molecular Immunology Group, said "a totally unconventional approach" would involve deliberately exposing human subjects to very low numbers of malaria parasites and targeting each protein with the organism.

Proteins are required for parasite survival and play an important role during the invasion process.

He said traditional immunisation efforts had only exposed subjects to one of a few proteins, which had resulted in partial protection and allowed the parasite to evolve and stunt the growth of various cells that would normally trigger an immune response.

"The current strategy to making the malaria vaccine is to find a single protein, like a silver bullet, and use that to immunise people to make an immune response which will protect against the entire organism," Prof Good said.

"That approach is still ongoing but it's very difficult ... mainly because small molecules are poorly immunogenic and the parasite has evolved ways to get around that type of immune response.

"So our approach is to use the entire organism, the whole parasite, but at a very, very low dose.

"What we've found ... is that the lower the dose of the parasites that we use the stronger the immune response."

Prof Good said if the first phase of the three phase trial was successful, a vaccine could be available "very soon after".

"If everything works out as we would hope, it could be available in three to five years," he said.

QIMR's initial study into malaria vaccines in mice was published last year in the online science journal, ScienceDirect.

Prof Good said QIMR would look to the World Health Organisation to administer the vaccine free to Third World countries while travellers would have to pay.

He believed the human trials of vaccine would be successful against all malaria strains.

"There are four main species of malaria and falciparum, which is the one we've done our studies on in humans to date, is by far the most deadly," he said.

"But this approach if it's successful in falciparum I would imagine it would also be successful in ... the other species of malaria."

Most malaria victims are aged under five in Africa, sea-east Asia and central south America.

Around 1000 imported cases are reported each year in Australia, which was declared malaria free in 1981.

A "talking version" of Rupert McCall's iconic poem Green and Gold Malaria is helping fund the research.

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