or the first time, a malaria vaccine that uses the entire malaria parasite has proven safe and shown promise to produce a strong immune response in a clinical trial. Though malaria has been largely eliminated in much of the developed world, it is still a widespread threat in warm, tropical areas where infected mosquitoes thrive, such as Africa. Malaria, caused by a parasite transmitted through the bite of an infected mosquito, kills nearly one million people and infects 300 million annually worldwide. The condition can be treated with anti-parasite drugs, but can have fatal consequences for vulnerable patients who have no immunity to the disease. Children under the age of five succumb at high rates to the neurological and cardiac effects of malaria, particularly in Africa.
Researchers found that the vaccine produced a partial protective response in the 80 volunteers who were immunized subcutaneously, or under the skin, by traditional needle and syringe in the trial at the Center for Vaccine Development in Baltimore. However, this response was significantly less than the 80 percent to 90 percent protective immunity the research team is intent on achieving. Researchers suspected that administering the vaccine more directly into the bloodstream, accelerating its path to the liver, might produce an even stronger response.
Scientists consider a whole parasite vaccine to be the “holy grail” of malaria vaccine research. Such a vaccine is believed to be more capable of broadly protecting people against the scores of varying strains of malaria. Historically, vaccines are comprised of various proteins found in the virus or, in the case of malaria, the parasite. Recombinant vaccines — those comprised of various components of the parasite — often are narrowly protective against just certain strains. Whole parasite vaccines have seemed unattainable because of the many challenges of large-scale production and preservation of whole parasites, which can only be produced by infecting mosquitoes with malaria-infected blood. Using mosquitoes raised in aseptic conditions, Sanaria Inc. developed a unique large-scale production and cryopreservation process, allowing the parasite to be frozen, shipped to remote locations and safely thawed.