United States: Researchers have tested a new malaria vaccine in a small trial and found it to be safe and effective. The vaccine works by targeting a later stage of the malaria parasite in the liver.
Immunization with a genetically modified Plasmodium falciparum parasite (GA2) induced a favorable immune response and was shown to have some protective efficacy against malaria infection.
Malaria is still a major health menace in most parts of the world, including sub-Saharan Africa, parts of Asia and Latin America, where nearly half a million of malaria deaths were recorded annually globally. The disease is disproportionately borne by young children and by pregnant women who stand in urgent need of more effective and longer lasting vaccination strategies.
As reported by the Medicalxpress, to push forward now is critical to prevent malaria from becoming an endemic disease in Europe, and new strategies are urgently needed to address disease eradication efforts that have stalled in light of their ineffectiveness today. There are current malaria vaccines that provide modest short term protection.
An alternative approach to functionally vaccinating against malaria involves exposure of the immune system to the full range of antigens present in a natural malaria infection using whole sporozoite vaccination with live attenuated parasites.
Once in the liver cells, GA2 permits the parasite to progress farther within the cell and provides the immune system with broader exposure to parasite antigens. It is hypothesized that exposure to the parasite is prolonged enough to facilitate more complete immune responses which in turn may improve ability of immune system to recognize and combat the parasite.
Healthy adult volunteers not previously exposed to malaria received random immunization with GA2, exposure to another malarial parasite, GA1, or were given a placebo of uninfected mosquito bites. The trial involved 25 participants, of which 10 were assigned to the GA2 group, 10 to the GA1 group and 5 to the placebo group. The group was both male and female volunteers.
The experiment, “Safety and Efficacy of Immunization with a Late Liver Stage Attenuated Malaria Parasite,” published in the New England Journal of Medicine, is a double blind, controlled clinical trial to measure the safety and side effect profile, as well as the efficacy, of immunization against malaria by mosquito bite with a genetically modified P. falciparum parasite (GA2) which continues to develop in the liver longer.