Malaria vaccine offers hope

The discovery by researchers of an antibody that halts the progress of malaria by caging its parasites in red blood cells, has raised fresh hopes of a remedy against a disease that claims more than 600,000 people a year worldwide. The team of scientists, led by Jonathan Kurtis, an immunologist at Brown University, US, found the antibody while investigating why 6 per cent of a group of 785 Tanzanian children possessed natural protection against malaria. Using blood samples and epidemiological data collected from the children, the researchers pinpointed a protein, PfSEA-1, which the parasites need in order to survive inside the red blood cells. They realised that the immune children were producing an antibody that locked PfSEA-1 into their red blood cells, stopping its spread. Kurtis said: “Researchers are trying to develop a malaria vaccine that prevents the parasite from entering the red blood cell. We have now found a way to block it from leaving the cell once it has entered and once it is trapped there, it cannot do any further damage.” Although the potential vaccine is yet to be tested on humans, trials on mice have yielded positive results. Despite being infected with a deadly form of malaria, the vaccinated rodents lived almost twice as long as unvaccinated ones and had far lower levels of malaria parasites. The vaccine will be tested on monkeys in the next month, and if the trial is successful, a clinical trial testing the vaccine in a small group of people could begin within 18 months. The research, published in the Science journal, could lead to the development of a vaccine that would prevent the progression of plasmodium falciparum malaria, which kills one child every 15 seconds in Africa and south-east Asia annually. “Our findings support PfSEA-1 as a potential vaccine candidate,” Kurtis added. Two existing approaches to vaccine development have sought to block the parasites from entering the liver or red blood cells. The new approach tries to bottle them up inside the red blood cells . Once the parasites remain trapped, they can be harmlessly gobbled up in the spleen by immune system cells called macrophages, Kurtis said. Dr Corine Karema, the head of malaria and other parasitic diseases division at the Rwanda Biomedical Centre (RBC) said the new approach only saves one from getting severe malaria but they can still catch the mild one. She noted that repeated trials on the vaccine are required to measure its exact effectiveness. Douglas Kavara, an infectious diseases’ specialist working with Duta clinic, Nyabugogo doubted the effectiveness of the antibody since it is yet to be tried on humans. “Similar trials have been successful on animals before but they usually fail when it comes to humans,” he noted. About 900,000 malaria cases were registered in 2013 and 409 people died as a result of the disease with 30 per cent of them being children under the age of five, according to information obtained from the health ministry On the other hand, malaria killed 627, 000 people in 2012, most of them children in sub-Saharan Africa, according to the World Health Organisation, Another malaria vaccine (RTSS), could be introduced in the world’s worst affected countries next year, after the latest trial of a treatment produced by GlaxoSmithKline, Britain’s biggest drug company, reduced the number of cases of the disease experienced by babies.

National

Malaria vaccine offers hope