MARKO SVICEVIC
A new malaria vaccine has shown promising results and has become the first vaccine of its type to possibly provide 100% protection against the disease. Before you start wondering who might be awarded the Nobel Prize for their discovery, it is important to note that the vaccine does have some drawbacks.
The World Health Organisation’s (WHO) latest figures from March show that there are an estimated 219 million cases of malaria each year which result in 660 000 annual deaths, with children under the age of five making up most of these deaths. This amounts to about 2 000 deaths a day. Science.discovery.com, however, goes as far as placing malaria in the ninth position in the list of the world’s deadliest diseases and states the death toll at over one million people each year. It remains unclear what the exact death toll is, as the WHO explains that in continents like Africa it is difficult to record accurate malaria related deaths, causing the WHO’s figures about these deaths to range between 490 000 to 836 000 globally.
According to an article by The New York Times, the vaccine called PfSPZ, developed by the American biotech company Sanaria Inc., gave full protection to a small number of volunteers. However, the vaccine was only effective under conditions deemed almost impossible to reproduce in malaria affected countries, such as the administration of the vaccine and the expenses involved.
Furthermore, the vaccine only protected 12 out of the 15 volunteers, and those 12 volunteers had to be administered higher dosages for the vaccine to be effective.
The idea behind the vaccine came from the knowledge that a person could naturally build up partial immunity against malaria if bitten by mosquitoes treated by radiation in a laboratory. But for this immunity to build up, you would need to be bitten roughly a thousand times.
To create the vaccine, the malaria-carrying mosquitoes are first bred in a laboratory and then irradiated. The malaria-causing parasite Plasmodium falciparum (the most dangerous of the malaria parasites) is then extracted from the mosquito. The then weakened parasites are counted and placed in vials. Thereafter, the weakened parasites can be injected directly into a person’s bloodstream and immunity against the disease can be built up.
Rebecca Morelle, a science reporter for the BBC’s World Service, says that the initial clinical trial included 40 volunteers who received different dosages of the vaccine and a further 17 who received a placebo. When exposed to the malaria parasite, the only volunteers who were not infected were those who received the highest doses of the vaccine. However, the next clinical trial on 15 volunteers showed that with the administration of high doses of the vaccine, only 3 were infected with the parasite.
Dr Robert Sedert from the Vaccine Research Centre at the National Institute of Health, told the BBC, “We were excited and thrilled by the result, but it is important that we repeat it, extend it and do it in larger numbers.” He also added that, “The next critical question will be whether the vaccine is durable over a long period of time and [whether] the vaccine protects against other strains of malaria.”
A Unicef article published on 14 August states that the vaccine will now be further tested in Africa, starting at the Ifakara Health Institute in Tanzania.
Although PfSPZ is still a candidate vaccine showing some promising results, it is not the only one. Another vaccine by the name of RTS, S/AS01, developed by the pharmaceutical company GlaxoSmithKline, has already shown some promising results. Although it is currently still being conducted, phase three of the clinical trial involved the vaccination of 15 450 children in seven African countries. This trial was conducted between March 2009 and January 2011 and aimed at studying the efficacy of the vaccine. Results from the trials showed that the vaccine protected African children against both clinical and severe malaria. Currently, there are about 20 possible malaria vaccines in clinical trials.
Although the results of these trials look promising, a successful vaccine to treat malaria is not yet on the market. It would be advised that people travelling first check whether their destination is a malaria-risk area. If there is a risk of contracting the disease, necessary precautions should be taken, which most commonly include specific malaria tablets.
As for the possibility of a vaccine as a preventative measure for malaria, hopes are certainly high as the impact of this disease on the African continent takes its toll. A malaria vaccine would not only aid governments in the fight against poverty, but would give millions a chance at life.
Image: Reinhard Nell
