A laboratory in Seattle has just announced that it has made promising progress towards developing a vaccine for malaria. Researchers at the Fred Hutchinson Cancer Research Center found that disabling three of the 5000 genes in the Plasmodium falciparum malaria parasite could ultimately enable the creation of a vaccine.
A global threat
Last year, malaria sickened 214 million and caused 438,000 deaths. It is caused by Plasmodium, a microscopic parasite spread to humans by mosquitoes. When a mosquito bites, it injects the Plasmodium parasites under the skin. From there, the parasites move to the liver where each one produces tens of thousands of copies of a new parasite form. These then spread out throughout the body, infecting red blood cells, causing the often fatal disease.
In this latest research, it appears that parasites become unable to move into the blood stream when three particular genes of P. falciparum are eliminated. This genetically-altered version of the parasite was previously tested on mice, and it was found that the rodents had total protection against malaria when later infected with an unmodified Plasmodium strain.
The research team then infected mosquitoes with the modified parasite and then placed 150 to 200 of these mosquitoes on the arms of ten human volunteers. None of them developed malaria in this first phase of human tests, and the vaccine triggered antibodies.
This is a welcome development as other malaria vaccines currently under development have several serious drawbacks. One of these, RTS,S, uses a genetically modified protein from P. falciparum but has been proven to be effective in only a third of patients. Another vaccine, PfSPZ, uses radiation to damage parasites’ DNA. It provides lasting protection to half of patients, but only after four impractical rounds of IV drips.
A long way still to go
However, these are still early days. Ten years of solid research led up to this early experiment and potentially at least one or more decades could pass before the strategy is proven to be safe and effective. This first batch of volunteers were not infected with full-strength parasites and it is not yet known whether their immune systems will be able to fend them off. This more challenging test will be conducted next year. And of course, mosquitoes are not a practical way to vaccine people, and an ease to administer injectable vaccine also needs to be developed.
Long-lasting insecticidal nets at forefront of prevention
Until then, TANA Netting will continue to develop and manufacture its WHOPES-recommended DawaPlus® long lasting insectidical net products, one of the most effective ways to prevent malaria. They dramatically reduce the number of bites a person gets from a mosquito, by up to 90%, and slash the risk of malaria transmission. This is why the systematic distribution of LLINs has been at the core of the WHO guidance on malaria prevention since 2007.