Completely and for a long time
Malaria vaccine has shown 100% long-term protection in humans
Svetlana Maslova, Hi-tech+
This result was recorded by scientists for the first time. So far, none of the vaccine candidates has shown such long-term protection. Although clinical studies are still ongoing, the authors believe that their drug will be an effective means to protect travelers and residents of malaria-endemic regions.
The PfSPZ vaccine was developed by the American biotechnology company Sanaria. Currently, the first phase of clinical trials has been completed and phase 2 continues.
PfSPZ was administered to participants in combination with one of the antimalarial drugs – pyrimethamine or chloroquine. Together with the latter, 100% protection against infection was recorded for three months. The results of the study are published in Nature (Mwakingwe-Omari et al., Two chemoattenuated PfSPZ malaria vaccines induce sterile hepatic immunity).
Malaria is caused by the pathogen Plasmodium. The PfSPZ vaccine contains one of its forms – purified Plasmodium falciparum sporozoites, which penetrate the liver through the blood and cause infection. In addition to the vaccine, the scientists assigned the volunteers to take either pyrimethamine, which kills the pathogen in the liver, or chloroquine, which works in the bloodstream.
Three months after vaccination and medication, participants were injected with the pathogen through the blood.
At low dosages, protection was weak. So, only two of the nine volunteers (taking pyrimethamine) were protected from malaria. The highest dosage already protected from 77.8% to 87.5%, depending on the strain of the pathogen.
The best result was shown by the combination of PfSPZ with chloroquine. All six participants showed 100% protection against malaria for at least three months after vaccination.
"These are unprecedented results for any of the malaria vaccines being developed," the authors said.
In their opinion, the vaccine can be a promising tool for both residents of endemic areas and tourists. Every year, more than 220 million people get sick with malaria and about 400 thousand die from infection.
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