A trial of a malaria vaccine that targets the most dangerous variety of parasite that causes the disease has shown some positive early results, BBC reports.
In a study of 121 men in Kenya, the vaccine which was developed at Oxford University, was 67% effective.
20 years of research later, encouraging results have now been recorded for 2 malaria vaccines.
Also, recent tests of a different vaccine in more advanced trials showed signs of it working in young children.
In the Oxford trial, published in Science Translational Medicine, scientists used two viruses, one a chimpanzee virus, to stimulate the body's immune system to produce cells that can fight against malaria.
Following up participants after 8 weeks, they found the vaccine had reduced the risk of malaria by two-thirds in those who had been given it.
Speaking on the development, Prof Adrian Hill, director of the Jenner Institute at the University of Oxford, said "such high efficacy in this first field trial is encouraging for further testing in children and infants who most need a malaria vaccine."
However, malaria transmission levels had been "unexpectedly low" during the trial, the study said, so it was difficult to know how the vaccine would have performed if the malaria risk had been high.
The Oxford researchers are now testing the safety of the vaccine in children and babies in Burkina Faso.
Malaria has been a serious killer in Sub-Saharan Africa and according to the World Health Organization, there were 198 million cases of malaria in 2013 and about 584,000 deaths related to the disease.