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Credit: Ute Frevert
and Margaret Shear
Investigators have reported success in the first clinical trial demonstrating controlled malaria infection in an African nation.
The study established that a product containing Plasmodium falciparum sporozoites can be used to safely infect volunteers with malaria in controlled lab conditions in a malaria-endemic country.
This represents a significant milestone in the search for new malaria drugs and vaccines, according to the investigators.
“We are extremely excited by the good results of this malaria challenge test, which opens up unprecedented opportunity for evaluation of new malaria drugs and vaccines in Africa,” said Salim Abdullah, PhD, of the Ifakara Health Institute Bagamoyo Research and Training Centre in Tanzania, where the study took place.
Dr Abdullah and his colleagues reported the results in the American Journal of Tropical Medicine and Hygiene. A related editorial is also available.
The researchers tested sporozoites that were grown in mosquitoes in the lab and then packaged in a purified, aseptic form acceptable for clinical trials. The product is known as PfSPZ Challenge and is owned by Sanaria, Inc., a privately held company in Rockville, Maryland.
Prior to this innovation, the ability to challenge a vaccine’s effectiveness required deliberately infecting vaccinated volunteers with malaria by exposing them to mosquito bites in an insectary.
Few such malaria insectaries exist, and due to the resources needed, these are limited to a handful in the US and Europe, far from the countries where malaria takes its toll.
This clinical trial established that injecting volunteers with cryopreserved, aseptic parasites can safely and effectively infect adult volunteers with P falciparum malaria in a malaria-endemic country.
“This innovation is a game-changer for malaria research and development in Africa,” said study author Stephen L. Hoffman, MD, of Sanaria, Inc. “This is about making available within Africa the same research tools to study malaria that we have in the USA and Europe.”
To test PfSPZ Challenge, the investigators recruited a group of 30 Tanzanian men, residents of Dar es Salaam, who had minimal exposure to malaria during the previous 5 years.
The volunteers were injected intradermally with 10,000 sporozoites (n=12), 25,000 sporozoites (n=11), or normal saline (n=6). Investigators and subjects were blinded to the intervention.
The investigators then compared the infection rate to that of volunteers who participated in a similar study in The Netherlands a few years ago.
After about 2 weeks, all but 2 of the 23 Tanzanian volunteers injected with sporozoites developed active infections, a rate similar to the Dutch volunteers.
Once active infection was established, the volunteers were immediately treated for malaria and cleared of parasites.
None of the volunteers developed serious side effects related to the study. Mild side effects included low-grade fever, headaches, and fatigue.
“This is a real step forward for developing a vaccine against malaria, which has killed more human beings throughout history than any other single cause,” said study author Christopher Plowe, MD, MPH, of the University of Maryland in Baltimore.
“The ability to safely administer malaria parasites by injection rather than by mosquito bite makes it possible to test new malaria vaccines, as well as drugs, anywhere in the world.” 
Credit: Ute Frevert
and Margaret Shear
Investigators have reported success in the first clinical trial demonstrating controlled malaria infection in an African nation.
The study established that a product containing Plasmodium falciparum sporozoites can be used to safely infect volunteers with malaria in controlled lab conditions in a malaria-endemic country.
This represents a significant milestone in the search for new malaria drugs and vaccines, according to the investigators.
“We are extremely excited by the good results of this malaria challenge test, which opens up unprecedented opportunity for evaluation of new malaria drugs and vaccines in Africa,” said Salim Abdullah, PhD, of the Ifakara Health Institute Bagamoyo Research and Training Centre in Tanzania, where the study took place.
Dr Abdullah and his colleagues reported the results in the American Journal of Tropical Medicine and Hygiene. A related editorial is also available.
The researchers tested sporozoites that were grown in mosquitoes in the lab and then packaged in a purified, aseptic form acceptable for clinical trials. The product is known as PfSPZ Challenge and is owned by Sanaria, Inc., a privately held company in Rockville, Maryland.
Prior to this innovation, the ability to challenge a vaccine’s effectiveness required deliberately infecting vaccinated volunteers with malaria by exposing them to mosquito bites in an insectary.
Few such malaria insectaries exist, and due to the resources needed, these are limited to a handful in the US and Europe, far from the countries where malaria takes its toll.
This clinical trial established that injecting volunteers with cryopreserved, aseptic parasites can safely and effectively infect adult volunteers with P falciparum malaria in a malaria-endemic country.
“This innovation is a game-changer for malaria research and development in Africa,” said study author Stephen L. Hoffman, MD, of Sanaria, Inc. “This is about making available within Africa the same research tools to study malaria that we have in the USA and Europe.”
To test PfSPZ Challenge, the investigators recruited a group of 30 Tanzanian men, residents of Dar es Salaam, who had minimal exposure to malaria during the previous 5 years.
The volunteers were injected intradermally with 10,000 sporozoites (n=12), 25,000 sporozoites (n=11), or normal saline (n=6). Investigators and subjects were blinded to the intervention.
The investigators then compared the infection rate to that of volunteers who participated in a similar study in The Netherlands a few years ago.
After about 2 weeks, all but 2 of the 23 Tanzanian volunteers injected with sporozoites developed active infections, a rate similar to the Dutch volunteers.
Once active infection was established, the volunteers were immediately treated for malaria and cleared of parasites.
None of the volunteers developed serious side effects related to the study. Mild side effects included low-grade fever, headaches, and fatigue.
“This is a real step forward for developing a vaccine against malaria, which has killed more human beings throughout history than any other single cause,” said study author Christopher Plowe, MD, MPH, of the University of Maryland in Baltimore.
“The ability to safely administer malaria parasites by injection rather than by mosquito bite makes it possible to test new malaria vaccines, as well as drugs, anywhere in the world.”
Credit: Ute Frevert
and Margaret Shear
Investigators have reported success in the first clinical trial demonstrating controlled malaria infection in an African nation.
The study established that a product containing Plasmodium falciparum sporozoites can be used to safely infect volunteers with malaria in controlled lab conditions in a malaria-endemic country.
This represents a significant milestone in the search for new malaria drugs and vaccines, according to the investigators.
“We are extremely excited by the good results of this malaria challenge test, which opens up unprecedented opportunity for evaluation of new malaria drugs and vaccines in Africa,” said Salim Abdullah, PhD, of the Ifakara Health Institute Bagamoyo Research and Training Centre in Tanzania, where the study took place.
Dr Abdullah and his colleagues reported the results in the American Journal of Tropical Medicine and Hygiene. A related editorial is also available.
The researchers tested sporozoites that were grown in mosquitoes in the lab and then packaged in a purified, aseptic form acceptable for clinical trials. The product is known as PfSPZ Challenge and is owned by Sanaria, Inc., a privately held company in Rockville, Maryland.
Prior to this innovation, the ability to challenge a vaccine’s effectiveness required deliberately infecting vaccinated volunteers with malaria by exposing them to mosquito bites in an insectary.
Few such malaria insectaries exist, and due to the resources needed, these are limited to a handful in the US and Europe, far from the countries where malaria takes its toll.
This clinical trial established that injecting volunteers with cryopreserved, aseptic parasites can safely and effectively infect adult volunteers with P falciparum malaria in a malaria-endemic country.
“This innovation is a game-changer for malaria research and development in Africa,” said study author Stephen L. Hoffman, MD, of Sanaria, Inc. “This is about making available within Africa the same research tools to study malaria that we have in the USA and Europe.”
To test PfSPZ Challenge, the investigators recruited a group of 30 Tanzanian men, residents of Dar es Salaam, who had minimal exposure to malaria during the previous 5 years.
The volunteers were injected intradermally with 10,000 sporozoites (n=12), 25,000 sporozoites (n=11), or normal saline (n=6). Investigators and subjects were blinded to the intervention.
The investigators then compared the infection rate to that of volunteers who participated in a similar study in The Netherlands a few years ago.
After about 2 weeks, all but 2 of the 23 Tanzanian volunteers injected with sporozoites developed active infections, a rate similar to the Dutch volunteers.
Once active infection was established, the volunteers were immediately treated for malaria and cleared of parasites.
None of the volunteers developed serious side effects related to the study. Mild side effects included low-grade fever, headaches, and fatigue.
“This is a real step forward for developing a vaccine against malaria, which has killed more human beings throughout history than any other single cause,” said study author Christopher Plowe, MD, MPH, of the University of Maryland in Baltimore.
“The ability to safely administer malaria parasites by injection rather than by mosquito bite makes it possible to test new malaria vaccines, as well as drugs, anywhere in the world.”