Vaccines to Protect Against Malaria
Each year, malaria causes more than one million deaths worldwide.
Combating malaria is critical to the military because our fighting forces are often deployed to areas where malaria is endemic. Researchers at the Naval Medical Research Center (NMRC) have been investigating methods to control and conquer this disease for more than two decades.
Creating An Effective Vaccine
NMRC researchers played a key role in determining the entire genetic sequence of the human parasite Plasmodium falciparum, the most deadly of the four malaria parasites that infect humans. The complexity of P. falciparum and the complicated nature of the disease make vaccine development a daunting task.
DNA vaccines induce the types of immune responses needed to kill the parasite, which hides within human cells. Researchers are investigating vaccine delivery platforms to boost the body's immune response.
A Promising Candidate
Program researchers, led by Captain Thomas Richie, M.D., Ph.D., have developed improved DNA-based vaccines by adding a second "boost" component based on genetically engineered viruses to enhance the immune system "primed" with DNA.
The team has filed an Investigational New Drug application with the FDA to test a product that is based on a recombinant adenovirus harboring DNA sequences from the malaria parasite. The adenovirus is genetically altered so it cannot cause illness.
Alternative Approaches
Another area of exploration involves identifying new malarial proteins using the genetic sequence of P. falciparum. Program staff have developed novel techniques to screen the multitude of antigens in the parasite, hoping to identify new ones that could be used to create a vaccine.
An additional area of exploration involves using the whole parasite as the vaccine. Infectious parasites are irradiated so that they cannot develop within the host for more than a few days. These attenuated parasites, however, still induce a very strong immune response.
Through the development of better vaccine components and improved vaccine delivery platforms, a vaccine to protect against malaria could be within reach.