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An investigational malaria vaccine can protect healthy adults from infection with a malaria strain different from that contained in the vaccine, according to a phase 1 study published in PNAS.
The vaccine, known as the PfSPZ Vaccine, contains weakened Plasmodium falciparum sporozoites that are able to generate a protective immune response against live malaria infection.
Prior research showed that the PfSPZ Vaccine can provide long-term protection against a single malaria strain matched to the vaccine.
The new study has shown that the PfSPZ Vaccine can protect against a different strain of P falciparum as well.
“An effective malaria vaccine will need to protect people living in endemic areas against multiple strains of the mosquito-borne disease,” said Anthony S. Fauci, MD, of the National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland.
“These new findings showing cross-protection with the PfSPZ Vaccine suggest that it may be able to accomplish this goal.”
The PfSPZ Vaccine was developed by Sanaria Inc. The company designed, manufactured, and provided PfSPZ Vaccine and the heterologous challenge mosquitoes for this trial. The NIAID supported the development of the vaccine through several grants.
Study details
The study enrolled 31 healthy, malaria-naive adults ages 19 to 45.
Fifteen subjects were scheduled to receive 3 doses of the PfSPZ Vaccine—9.0 × 105 PfSPZ administered intravenously 3 times at 8-week intervals. The remaining subjects served as controls.
Nineteen weeks after receiving the final dose of the test vaccine, vaccinated subjects and controls were exposed to bites from mosquitoes infected with the same strain of P falciparum parasites (NF54) that were used to manufacture PfSPZ Vaccine.
Nine of the 14 subjects (64%) who received PfSPZ Vaccine demonstrated no evidence of malaria parasites. All 6 of the non-vaccinated subjects who were challenged at the same time had malaria parasites in their blood.
Of the 9 subjects who showed no evidence of malaria, 6 subjects were again exposed to mosquito bites, this time from mosquitoes infected with a different strain of P falciparum (Pf7G8), 33 weeks after the final immunization.
In this group, 5 of the 6 subjects (83%) were protected against malaria infection. None of the 6 control subjects who were challenged were protected.
“Achieving durable protection against a malaria strain different from the vaccine strain, over 8 months after vaccination, is an indication of this vaccine’s potential,” said Robert A. Seder, MD, of NIAID.
“If we can build on these findings with the PfSPZ Vaccine and induce higher efficacy, we may be on our way to a vaccine that could effectively protect people against a variety of malaria parasites where the disease is prevalent.”
The researchers found the PfSPZ Vaccine activated T cells and induced antibody responses in all vaccine recipients. Vaccine-specific T-cell responses were comparable when measured against both malaria challenge strains, providing some insight into how the vaccine was mediating protection.
Ongoing research should determine whether protective efficacy can be improved by changes to the PfSPZ Vaccine dose and number of immunizations.
A phase 2 trial testing 3 different dosages in a 3-dose vaccine regimen is now underway in 5-to 12-month-old infants in Western Kenya to assess safety and efficacy of the vaccine against natural infection. 
An investigational malaria vaccine can protect healthy adults from infection with a malaria strain different from that contained in the vaccine, according to a phase 1 study published in PNAS.
The vaccine, known as the PfSPZ Vaccine, contains weakened Plasmodium falciparum sporozoites that are able to generate a protective immune response against live malaria infection.
Prior research showed that the PfSPZ Vaccine can provide long-term protection against a single malaria strain matched to the vaccine.
The new study has shown that the PfSPZ Vaccine can protect against a different strain of P falciparum as well.
“An effective malaria vaccine will need to protect people living in endemic areas against multiple strains of the mosquito-borne disease,” said Anthony S. Fauci, MD, of the National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland.
“These new findings showing cross-protection with the PfSPZ Vaccine suggest that it may be able to accomplish this goal.”
The PfSPZ Vaccine was developed by Sanaria Inc. The company designed, manufactured, and provided PfSPZ Vaccine and the heterologous challenge mosquitoes for this trial. The NIAID supported the development of the vaccine through several grants.
Study details
The study enrolled 31 healthy, malaria-naive adults ages 19 to 45.
Fifteen subjects were scheduled to receive 3 doses of the PfSPZ Vaccine—9.0 × 105 PfSPZ administered intravenously 3 times at 8-week intervals. The remaining subjects served as controls.
Nineteen weeks after receiving the final dose of the test vaccine, vaccinated subjects and controls were exposed to bites from mosquitoes infected with the same strain of P falciparum parasites (NF54) that were used to manufacture PfSPZ Vaccine.
Nine of the 14 subjects (64%) who received PfSPZ Vaccine demonstrated no evidence of malaria parasites. All 6 of the non-vaccinated subjects who were challenged at the same time had malaria parasites in their blood.
Of the 9 subjects who showed no evidence of malaria, 6 subjects were again exposed to mosquito bites, this time from mosquitoes infected with a different strain of P falciparum (Pf7G8), 33 weeks after the final immunization.
In this group, 5 of the 6 subjects (83%) were protected against malaria infection. None of the 6 control subjects who were challenged were protected.
“Achieving durable protection against a malaria strain different from the vaccine strain, over 8 months after vaccination, is an indication of this vaccine’s potential,” said Robert A. Seder, MD, of NIAID.
“If we can build on these findings with the PfSPZ Vaccine and induce higher efficacy, we may be on our way to a vaccine that could effectively protect people against a variety of malaria parasites where the disease is prevalent.”
The researchers found the PfSPZ Vaccine activated T cells and induced antibody responses in all vaccine recipients. Vaccine-specific T-cell responses were comparable when measured against both malaria challenge strains, providing some insight into how the vaccine was mediating protection.
Ongoing research should determine whether protective efficacy can be improved by changes to the PfSPZ Vaccine dose and number of immunizations.
A phase 2 trial testing 3 different dosages in a 3-dose vaccine regimen is now underway in 5-to 12-month-old infants in Western Kenya to assess safety and efficacy of the vaccine against natural infection.
An investigational malaria vaccine can protect healthy adults from infection with a malaria strain different from that contained in the vaccine, according to a phase 1 study published in PNAS.
The vaccine, known as the PfSPZ Vaccine, contains weakened Plasmodium falciparum sporozoites that are able to generate a protective immune response against live malaria infection.
Prior research showed that the PfSPZ Vaccine can provide long-term protection against a single malaria strain matched to the vaccine.
The new study has shown that the PfSPZ Vaccine can protect against a different strain of P falciparum as well.
“An effective malaria vaccine will need to protect people living in endemic areas against multiple strains of the mosquito-borne disease,” said Anthony S. Fauci, MD, of the National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland.
“These new findings showing cross-protection with the PfSPZ Vaccine suggest that it may be able to accomplish this goal.”
The PfSPZ Vaccine was developed by Sanaria Inc. The company designed, manufactured, and provided PfSPZ Vaccine and the heterologous challenge mosquitoes for this trial. The NIAID supported the development of the vaccine through several grants.
Study details
The study enrolled 31 healthy, malaria-naive adults ages 19 to 45.
Fifteen subjects were scheduled to receive 3 doses of the PfSPZ Vaccine—9.0 × 105 PfSPZ administered intravenously 3 times at 8-week intervals. The remaining subjects served as controls.
Nineteen weeks after receiving the final dose of the test vaccine, vaccinated subjects and controls were exposed to bites from mosquitoes infected with the same strain of P falciparum parasites (NF54) that were used to manufacture PfSPZ Vaccine.
Nine of the 14 subjects (64%) who received PfSPZ Vaccine demonstrated no evidence of malaria parasites. All 6 of the non-vaccinated subjects who were challenged at the same time had malaria parasites in their blood.
Of the 9 subjects who showed no evidence of malaria, 6 subjects were again exposed to mosquito bites, this time from mosquitoes infected with a different strain of P falciparum (Pf7G8), 33 weeks after the final immunization.
In this group, 5 of the 6 subjects (83%) were protected against malaria infection. None of the 6 control subjects who were challenged were protected.
“Achieving durable protection against a malaria strain different from the vaccine strain, over 8 months after vaccination, is an indication of this vaccine’s potential,” said Robert A. Seder, MD, of NIAID.
“If we can build on these findings with the PfSPZ Vaccine and induce higher efficacy, we may be on our way to a vaccine that could effectively protect people against a variety of malaria parasites where the disease is prevalent.”
The researchers found the PfSPZ Vaccine activated T cells and induced antibody responses in all vaccine recipients. Vaccine-specific T-cell responses were comparable when measured against both malaria challenge strains, providing some insight into how the vaccine was mediating protection.
Ongoing research should determine whether protective efficacy can be improved by changes to the PfSPZ Vaccine dose and number of immunizations.
A phase 2 trial testing 3 different dosages in a 3-dose vaccine regimen is now underway in 5-to 12-month-old infants in Western Kenya to assess safety and efficacy of the vaccine against natural infection.