Last week U.S. scientists with the biotech company, Sanaria, announced a possible breakthrough on an experimental malaria vaccine: an early trial led to a success rate of 80 percent for the two highest doses. Malaria remains one of the world's worst scourges.

 

The new vaccine, known as PfSPZ, was created by using live malaria parasites (Plasmodium falciparum) that have been weakened by radiation. Although mosquitoes carry malaria, it's actually the parasites inside the mosquitoes that cause the disease. Scientists have long known that repeated exposure to malaria could eventually lead to immunity; however the exposure threshold is extremely high. Experts estimate that one would need to be bit by 1,000 parasite-carrying mosquitoes in order to develop immunity.

 

Sanaria worked with 57 volunteers on the trial, known of whom had previously contracted malaria. For those given four injections of the new vaccine, two-thirds became immune. However, for all of those given five doses achieved immunity. Still, the trial was small.

 

A number of hurdles remain for scaling up the vaccines, however. The vaccine currently requires mosquito dissectors, which have to manually remove parasites. Furthermore, a vaccine that requires five doses and must be injected into the vein means high expense and practicality issues, especially for the people most prone to malaria: the rural poor.

 

However, experts are confident that many of these hurdles can be overcome, either through further work on PfSPZ or other malaria vaccines under development.

 

Some experts believe that malaria has killed more people in history than any other disease. According to the WHO, malaria kills a child in Africa every minute.