Scientists involved in the trial of a vaccine against malaria say they are optimistic they can defeat the disease. Early tests of the vaccine showed it could provide complete protection for some people.<br /><br />The scientists have now launched trials in Kenya to see if the vaccine is as effective in the wider population.<br /><br />There are over 300 million cases of malaria around the world each year and it claims more than one million lives.<br /><br />More than 90 per cent of cases are reported in sub-Saharan Africa, where it is the main cause of death and a major threat to children.<br /><br />There is currently no effective vaccine against the disease.<br /><br />A malaria vaccine has eluded scientists not least because the parasite which carries the disease evolves rapidly and can become resistant to drugs.<br /><br />To mark World Malaria Day,Al Jazeera's Catherine Soi reports from Siaya in western Kenya, part of Africa's so-called malaria belt, where doctors are conducting trials for a vaccine that promises to eradicate the disease once and for all.
