Researchers develop novel strategy to develop 'next-generation' malaria vaccines that will help targeting the long-term goal of eliminating and eradicating the deadly mosquito-borne disease.
While trials are underway testing the efficacy if GlaxoSmithKline Biologicals' (GSK Bio) RTS, S malaria vaccine, experts linked to PATH Malaria Vaccine Initiative (MVI) have suggested new approaches.
While most malaria vaccine candidates use one or more components of the malaria parasite to elicit an immune response, another approach uses a weakened form of the whole parasite.
MVI is working with Sanaria Inc. to develop a novel vaccine candidate that uses this approach with Plasmodium falciparum. It is currently being tested in adult volunteers in the United States.
Like RTS,S, many of these studies are focused on the pre-erythrocytic approach. They aim to trigger the immune system to defend against the parasite as soon as it enters a person's bloodstream or infects liver cells.
This prevents the parasite from maturing and multiplying in the liver, reentering the bloodstream, and infecting red blood cells.
Another approach targets the malaria parasite when it is most destructive: at the blood stage, when the parasite replicates rapidly in red blood cells. Blood-stage vaccines are not expected to block all infection. Instead, they aim to decrease the number of parasites in the blood, reducing the severity of malaria.
The researchers are also looking for vaccine candidates that block the transmission of malaria from mosquitoes to humans.
Transmission-blocking vaccines attempt to interrupt the life cycle of the parasite by inducing antibodies that prevent the parasite from maturing in the mosquito after it bites a vaccinated person.
The researchers also aim to develop vaccines against P. vivax, the less severe but more widespread malaria parasite affecting humans.
MVI plans to intensify its support for vivax approaches in hopes of eventually combining them with vaccines targeting P. falciparum.
As the number of potential malaria vaccine candidates increases, scientists will need new and better technologies to assess their potential efficacy and decide which should go forward.
MVI is supporting the refinement and development of both laboratory tools and methodologies for evaluating vaccine candidates in humans.