Australasian Science: Australia's authority on science since 1938

Malaria Vaccine Trials Funded

By Stephen Luntz

Funding has been received for trials of an all-Australian malaria vaccine using a different strategy to previous unsuccessful trials.

Malaria is usually thought to take 700,000 lives each year but may kill more (AS, May 2012, p.7), while hundreds of millions get sick. Dr Krystal Evans of the Walter and Eliza Hall Institute says there is “hot debate” as to whether it is better to target the liver stage of the parasite’s lifecycle, after it first enters the body from mosquito saliva, or the subsequent blood stage.

“The liver stage is when there are the fewest parasites in the body, so it represents a potential bottleneck,” says Evans. However, “if you don’t get 100% protection in the liver you will see malarial disease when the parasites break out into the blood”.

Consequently, Evans has focused her research on the time when the parasites are in the blood, causing fever, chills, headaches, and in serious cases severe anaemia and cerebral malaria. “We’re trying to mimic the fact that people become immune to malaria eventually, although it can take a long time,” says Evans.

Evans’ approach is to genetically modify malaria parasites so they clear from the body quickly and don’t cause disease. She’s been awarded an NHMRC grant she says “will allow us to manufacture the vaccine in sufficient quantities, and to high enough standards, for human trials”.

Manufacturing will be done by Prof James McCarthy of the Queensland Institute of Medical Research, who has a long history of both producing malaria parasites for testing and conducting human trials. “People are more altruistic than you might think,” says Evans. “They want to see malaria abolished in their lifetimes and they are willing to take part in trials to do so.”

As well as establishing safety, the trials will allow Evans to test for T cell response, which may indicate alterations that provide protection against wild strain malaria infection.

Evans says the long-term goal is to use the vaccine she has created as a platform, “a sort of modular plug and play” to host modifications, such as a vaccine that will force the parasite to express proteins during the blood stage that are currently restricted to the liver stage. This could lead to a vaccine effective against both stages of the parasite’s lifecycle, as well as one that could prevent transmission from an infected person to a mosquito.