A small trial of a malaria vaccine in Mali showed promising results, according to results published in the United States.
The vaccine elicited a strong immune response among 40 adults who received it, all of whom tolerated the vaccine "very well," the National Institute of Allergy and Infectious Diseases said in a statement Tuesday.
It was the first trial on the candidate vaccine, designed to block the malaria parasite from entering human blood cells, the statement said.
A second trial involving 400 Malian children aged one to six years old is now underway.
Malaria is one of the deadliest diseases in Africa and in developing countries. It kills more than one million people each year, most of them children.
Research for the study was led by Mahamadou Thera at the University of Bamako, Mali, with support from the National Institute of Allergy and Infectious Diseases, part of the US National Institutes of Health (NIH).
The researchers recruited study participants in Bandiagra, a small town in northeastern Mali where malaria is prevalent.
At the peak of the rainy season in August and September, people in this part of Mali typically get up to 60 malaria-transmitting mosquito bites per month, the researchers said.
Volunteers received three injections, spaced one month apart, of the vaccine or a licensed rabies vaccine, as a control.
At the start of the study, all volunteers had high levels of antibodies against malaria in their blood, showing they had had prior exposure to the parasite, the researchers said.
Those who received the candidate vaccine showed up to a sixfold rise of vaccine-specific antibodies, while the levels of antibodies declined among those who received the rabies vaccine, it said.