A weakened strain of the malaria parasite, created by a team of Australian scientists, in collaboration with researchers from the US, Japan and Canada, will be used as a live vaccine against the disease.
The vaccine will be trailed in humans from early next year at the Walter Reed Army Institute of Research in Maryland, US.
AdvertisementAn article in the Proceedings of the National Academy of Sciences USA outlines how the researchers deleted two key genes in the Plasmodium falciparum parasite - which causes the form of malaria most deadly to humans - while developing the vaccine.
By removing the genes, the malaria parasite is halted during its liver infection phase, preventing it from spreading to the blood stream where it can cause severe disease and death.
Professor Alan Cowman, head of Melbourne's Walter and Eliza Hall Institute's Infection and Immunity division, said similar vaccines had been tested in mice and offered 100 per cent protection against malaria infection.
He said it was hoped the vaccine would produce similar results in humans.
"Although two genes have been deleted the parasite is still alive and able to stimulate the body's protective immune system to recognize and destroy incoming mosquito-transmitted deadly parasites," Cowman said.
This approach to vaccine development - using a weakened form of the whole organism that causes a particular disease - has proven successful in eradicating smallpox and controlling diseases such as flu and polio.
Cowman said the research team had used knowledge from several decades ago - when scientists proved that irradiated malaria parasites provide protection against subsequent malaria infection in animal models and humans - in developing the vaccine.
"Although vaccines are under development that use whole malaria parasites weakened by irradiation to protect against infection, their safety and effectiveness rely on a precise irradiation dose and trial results have been variable," Cowman said.
"We believe that our genetically attenuated parasite approach provides a safe and reproducible way of developing a whole organism malaria vaccine," Cowman added.
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