Virus-based vaccine against malaria proves 67 per cent effective
09 May 2015
A new malaria vaccine that uses viruses carrying malaria antigen has shown promising results in field trials. The vaccine, which stimulates the immune system to resist the pathogen, was 67 per cent effective against one of the parasites that caused malaria.
The international consortium which conducted the Kenyan trial report published its findings in the journal Science Translational Medicine.
The vaccine, developed by the Jenner Institute at Oxford University in the UK, was found to be 67 per cent effective at protecting against infection by Plasmodium falciparum, in a study of 121 men in Kenya.
Malaria is caused by the Plasmodium parasite, which is carried to a host from the bite of a female mosquito carrying the parasite.
According to experts, a safe and effective malaria vaccine could drastically reduce the huge social and economic burden of a disease that kills hundreds of thousands of people a year - most of them young children in sub-Saharan Africa.
The second malaria vaccine now developed comes after decades of research. Another vaccine - recently tested in more advanced trials - was shown to be partially effective in protecting children for up to 4 years.
The new vaccine has two virus "vectors" encoded with a key protein or antigen for Plasmodium falciparum that triggered the immune system to produce T-cells to protect against malaria.
With about 1,300 children dying in sub-Saharan Africa from malaria every day, scientists wanted a vaccine to protect those most at risk.
The World Health Organisation reported that there were 198 million cases of malaria in 2013 and about 584,000 deaths related to the disease.
However, it had taken scientists over two decades to make any real progress, due mainly to the differing nature of parasites transmitted to people through the bites of infected mosquitoes.
Four different parasites are known to cause malaria. It remains unknown whether the Oxford vaccine protected against all variants of the Plasmodium falciparum parasite or just one.
According to the report on the Oxford trial, which was published in Science Translational Medicine, the researchers used two viruses, with one a chimpanzee virus - to stimulate the body's immune system to produce cells that can fight against malaria.
This novel "viral vectored" vaccine targets the parasite in the liver.
The participants were followed up after eight weeks; the vaccine had reduced the risk of malaria by two-thirds in those who had received it.
