The new malaria vaccine is being tentatively named ‘PfSPZ’ and is unique as it contains sporozoites (SPZ) – a life cycle stage of live but weakened malaria Plasmodium falciparum parasites.
Details of the Phase-1 clinical trial were published yesterday in the journal Science. Developers of the vaccine say that the weakened, early stage parasites can actually help a person build up an immunity following an injection of a high enough dosage into the bloodstream.
Lead author Dr Robert Seder, from the Vaccine Research Center at the National Institutes of Health, in Maryland, said: “We were excited and thrilled by the result, but it is important that we repeat it, extend it and do it in larger numbers.”
It has been common knowledge amongst health experts for several decades that exposure to mosquitoes treated with radiation is highly effective as a malaria prevention method.
Unfortunately, evidence shows that roughly 1,000 mosquito bites are required over a time period to gradually develop a sufficient level of immunity. Therefore, it is simply an unfeasible way to protect people.
Dr Seder added: “Based on the history, we knew dose was important because you needed 1,000 mosquito bites to get protection – this validates that. It allows us in future studies to increase the dose and alter the schedule of the vaccine to further optimise it. The next critical questions will be whether the vaccine is durable over a long period of time and can the vaccine protect against other strains of malaria.”
The new vaccine is being developed by a biotech company called Sanaria, based in Maryland, U.S., who irradiated lab-grown mosquitoes before extracting the malaria-causing parasite Plasmodium falciparum.
Their Phase-1 clinical trial of PfSPZ involved 57 volunteers aged 18 to 45 who had no previous history of the malaria disease. The researchers administered varying strengths of PfSPZ to 40 of the participants and the other 17 received no vaccine whatsoever.
After a week’s analysis, no severe side effects were noted in any of the participants in the study. However, to determine how effective the malaria vaccine actually was, each person – including those who didn’t receive the vaccine – was exposed to bites from five malaria infected mosquitoes.
A week later everybody was analysed for infection and those not given the vaccine received treatment for malaria. It was found that those given high doses were significantly less likely to contract malaria in comparison to the others in the study.
Just three of the 15 participants who received higher doses actually became infected. However, 16 of 17 participants in the lower dosage group became infected and 11 of the 12 participants who were not vaccinated then became infected.
The study, conducted between October 2011 and October 2012, was hugely promising due to the fact none of the participants experienced any side effects from the vaccine. However, the researchers admit it could be years before the vaccine is available in communities where it is needed.
Dr William Schaffner, head of the preventive medicine department at Vanderbilt University’s medical school, said although it was a ‘scientific advance’, it could be as long as a 10 year wait before the malaria vaccine is scientifically proved, given approval, and made available for distribution.
He told CCN: “This is not a vaccine that’s ready for travellers to the developing world anytime soon. However, from the point of view of science dealing with one of the big-three infectious causes of death around the world, it’s a notable advance. And everybody will be holding their breath, watching to see whether this next trial works and how well it works.”
Of course, if you are travelling abroad in the next 10 years and need malaria prevention and treatment, there are other medications available right now. These include Doxycycline, Malarone, Paludrine, and Jungle Formula Maximum Pump Spray. In addition, don’t forget to check the NHS Fit For Travel website where you will find the recommended malaria medication for your destination.
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