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A novel vaccination approach can offer 100% protection against malaria, according to research published in Nature.
The approach involved direct venous inoculation of aseptic, purified, cryopreserved, non-irradiated Plasmodium falciparum sporozoites (PfSPZ) in healthy adults taking chloroquine for antimalarial chemoprophylaxis (PfSPZ-CVac).
At the optimal dose and schedule, PfSPZ-CVac prevented infection in 9 of 9 volunteers, and this protection lasted 10 weeks after the last dose.
In addition, researchers said PfSPZ-CVac was well-tolerated.
PfSPZ was provided by Sanaria. This research was supported by federal funding and the Bill and Melinda Gates Foundation.
Treatment and challenge
The researchers tested PfSPZ-CVac in healthy adults, ages 18 to 45, who were malaria-naive. They received different doses of PfSPZ at different intervals and different doses/schedules of chloroquine.
In the first part of the study, test subjects received 3 doses of PfSPZ at 3.2 × 103 (n=9), 1.28 × 104 (n=9), or 5.12 × 104 (n=9), and controls (n=13) received 3 doses of normal saline.
Doses were given at 28-day intervals, and controlled human malaria infection (CHMI) was performed at 8 to 10 weeks after immunization.
In the second part of the study, test subjects received 3 doses of PfSPZ at 5.12 × 104 at 14-day intervals (n=9) or 5-day intervals (n=9), and controls (n=6) received 3 doses of normal saline.
CHMI was performed at 10 weeks post-immunization.
Most subjects received chloroquine at a base loading dose of 10 mg kg-1 or 620 mg two days before the first dose of PfSPZ, whichever dose was less, followed by weekly doses of 5 mg kg-1 or 310 mg through 5 days after the last dose of PfSPZ. Subjects who were immunized on days 0, 5, and 10 received chloroquine on days 0, 5, 10, and 15.
Results
All controls, who received normal saline plus chloroquine, developed parasitemia.
However, 3 doses of PfSPZ at 5.12 × 104, given at 28-day intervals, prevented infection in 9 of 9 subjects (100%).
The 3.2 × 103 dose of PfSPZ (also given at 28-day intervals) protected 3 of 9 subjects (33%), and the 1.28 × 104 dose protected 6 of 9 subjects (67%).
Three doses of PfSPZ at 5.12 × 104, given at 5-day intervals, protected 5 of 8 subjects (63%). And 3 doses of PfSPZ at 5.12 × 104, given at 14-day intervals, protected 6 of 9 subjects (67%).
“By vaccinating with a live, fully active pathogen, it seems clear that we were able to set off a very strong immune response,” said study author Benjamin Mordmüller, of the University of Tübingen in Germany.
“Additionally, all the data we have so far indicate that what we have here is relatively stable, long-lasting protection.”
“That protection was probably caused by specific T lymphocytes and antibody responses to the parasites in the liver,” added Peter Kremsner, also of the University of Tübingen.
The researchers said there were no serious adverse events, and the frequencies of grade 1-3 events were similar in subjects who received PfSPZ-CVac and controls.
Chloroquine was considered well-tolerated, although 2 subjects discontinued the trial after the loading dose because they experienced nausea and vomiting. 
A novel vaccination approach can offer 100% protection against malaria, according to research published in Nature.
The approach involved direct venous inoculation of aseptic, purified, cryopreserved, non-irradiated Plasmodium falciparum sporozoites (PfSPZ) in healthy adults taking chloroquine for antimalarial chemoprophylaxis (PfSPZ-CVac).
At the optimal dose and schedule, PfSPZ-CVac prevented infection in 9 of 9 volunteers, and this protection lasted 10 weeks after the last dose.
In addition, researchers said PfSPZ-CVac was well-tolerated.
PfSPZ was provided by Sanaria. This research was supported by federal funding and the Bill and Melinda Gates Foundation.
Treatment and challenge
The researchers tested PfSPZ-CVac in healthy adults, ages 18 to 45, who were malaria-naive. They received different doses of PfSPZ at different intervals and different doses/schedules of chloroquine.
In the first part of the study, test subjects received 3 doses of PfSPZ at 3.2 × 103 (n=9), 1.28 × 104 (n=9), or 5.12 × 104 (n=9), and controls (n=13) received 3 doses of normal saline.
Doses were given at 28-day intervals, and controlled human malaria infection (CHMI) was performed at 8 to 10 weeks after immunization.
In the second part of the study, test subjects received 3 doses of PfSPZ at 5.12 × 104 at 14-day intervals (n=9) or 5-day intervals (n=9), and controls (n=6) received 3 doses of normal saline.
CHMI was performed at 10 weeks post-immunization.
Most subjects received chloroquine at a base loading dose of 10 mg kg-1 or 620 mg two days before the first dose of PfSPZ, whichever dose was less, followed by weekly doses of 5 mg kg-1 or 310 mg through 5 days after the last dose of PfSPZ. Subjects who were immunized on days 0, 5, and 10 received chloroquine on days 0, 5, 10, and 15.
Results
All controls, who received normal saline plus chloroquine, developed parasitemia.
However, 3 doses of PfSPZ at 5.12 × 104, given at 28-day intervals, prevented infection in 9 of 9 subjects (100%).
The 3.2 × 103 dose of PfSPZ (also given at 28-day intervals) protected 3 of 9 subjects (33%), and the 1.28 × 104 dose protected 6 of 9 subjects (67%).
Three doses of PfSPZ at 5.12 × 104, given at 5-day intervals, protected 5 of 8 subjects (63%). And 3 doses of PfSPZ at 5.12 × 104, given at 14-day intervals, protected 6 of 9 subjects (67%).
“By vaccinating with a live, fully active pathogen, it seems clear that we were able to set off a very strong immune response,” said study author Benjamin Mordmüller, of the University of Tübingen in Germany.
“Additionally, all the data we have so far indicate that what we have here is relatively stable, long-lasting protection.”
“That protection was probably caused by specific T lymphocytes and antibody responses to the parasites in the liver,” added Peter Kremsner, also of the University of Tübingen.
The researchers said there were no serious adverse events, and the frequencies of grade 1-3 events were similar in subjects who received PfSPZ-CVac and controls.
Chloroquine was considered well-tolerated, although 2 subjects discontinued the trial after the loading dose because they experienced nausea and vomiting.
A novel vaccination approach can offer 100% protection against malaria, according to research published in Nature.
The approach involved direct venous inoculation of aseptic, purified, cryopreserved, non-irradiated Plasmodium falciparum sporozoites (PfSPZ) in healthy adults taking chloroquine for antimalarial chemoprophylaxis (PfSPZ-CVac).
At the optimal dose and schedule, PfSPZ-CVac prevented infection in 9 of 9 volunteers, and this protection lasted 10 weeks after the last dose.
In addition, researchers said PfSPZ-CVac was well-tolerated.
PfSPZ was provided by Sanaria. This research was supported by federal funding and the Bill and Melinda Gates Foundation.
Treatment and challenge
The researchers tested PfSPZ-CVac in healthy adults, ages 18 to 45, who were malaria-naive. They received different doses of PfSPZ at different intervals and different doses/schedules of chloroquine.
In the first part of the study, test subjects received 3 doses of PfSPZ at 3.2 × 103 (n=9), 1.28 × 104 (n=9), or 5.12 × 104 (n=9), and controls (n=13) received 3 doses of normal saline.
Doses were given at 28-day intervals, and controlled human malaria infection (CHMI) was performed at 8 to 10 weeks after immunization.
In the second part of the study, test subjects received 3 doses of PfSPZ at 5.12 × 104 at 14-day intervals (n=9) or 5-day intervals (n=9), and controls (n=6) received 3 doses of normal saline.
CHMI was performed at 10 weeks post-immunization.
Most subjects received chloroquine at a base loading dose of 10 mg kg-1 or 620 mg two days before the first dose of PfSPZ, whichever dose was less, followed by weekly doses of 5 mg kg-1 or 310 mg through 5 days after the last dose of PfSPZ. Subjects who were immunized on days 0, 5, and 10 received chloroquine on days 0, 5, 10, and 15.
Results
All controls, who received normal saline plus chloroquine, developed parasitemia.
However, 3 doses of PfSPZ at 5.12 × 104, given at 28-day intervals, prevented infection in 9 of 9 subjects (100%).
The 3.2 × 103 dose of PfSPZ (also given at 28-day intervals) protected 3 of 9 subjects (33%), and the 1.28 × 104 dose protected 6 of 9 subjects (67%).
Three doses of PfSPZ at 5.12 × 104, given at 5-day intervals, protected 5 of 8 subjects (63%). And 3 doses of PfSPZ at 5.12 × 104, given at 14-day intervals, protected 6 of 9 subjects (67%).
“By vaccinating with a live, fully active pathogen, it seems clear that we were able to set off a very strong immune response,” said study author Benjamin Mordmüller, of the University of Tübingen in Germany.
“Additionally, all the data we have so far indicate that what we have here is relatively stable, long-lasting protection.”
“That protection was probably caused by specific T lymphocytes and antibody responses to the parasites in the liver,” added Peter Kremsner, also of the University of Tübingen.
The researchers said there were no serious adverse events, and the frequencies of grade 1-3 events were similar in subjects who received PfSPZ-CVac and controls.
Chloroquine was considered well-tolerated, although 2 subjects discontinued the trial after the loading dose because they experienced nausea and vomiting.