A small trial has shown that a new vaccine is 100 percent effective at preventing malaria, bringing hope to the frustrating fight against a disease that can worsen the course of HIV and vice versa. However, such an encouraging milestone is tempered by the fact that the administration of the vaccine, which requires multiple intravenous doses, poses major logistical challenges for its use in the parts of the world where it is needed the most. Also, as of yet, there is no data on how long its protection may last. The vaccine was created by infecting mosquitoes with malaria parasites, treating them with radiation, removing the salivary glands and then purifying the radiation-weakened parasites. The vaccine can then prompt an anti-malaria immune response in the human body without actually causing malaria. An estimated 200 million people worldwide are infected with malaria each year, about 600,000 of whom will die of the disease.