We would like to express our gratitude to the study participants. We also thank the members of the Safety Monitoring Committee (Feliciano Panades Shumad—local safety monitor, James Campbell—SMC chair, Mark Riddle, and Brian Greenwood) for their thoughtful oversight, the entire study team of the Equatorial Guinea Malaria Vaccine Initiative (EGMVI) for carrying out the study, and the teams at Sanaria and Protein Potential for manufacture and shipping of IPs (PfSPZ Vaccine, PfSPZ Challenge, diluents, and NS), for immunoassays, and for regulatory, quality, clinical, pharmaceutical operations, legal, and administrative support; and for the administrative support of Medical Care Development International. We are grateful to the continued support of the Equatorial Guinea Ministry of Health and Social Welfare who enable all studies in Equatorial Guinea to proceed.
Epstein JE et al.2011. Live attenuated malaria vaccine designed to protect through hepatic CD8+T cell immunity. Science 334: 475–480.
Seder RA et al.2013. Protection against malaria by intravenous immunization with a nonreplicating sporozoite vaccine. Science 341: 1359–1365.
Ishizuka AS et al.2016. Protection against malaria at 1 year and immune correlates following PfSPZ Vaccination. Nat Med 22: 614–623.
Lyke KE et al.2017. Attenuated PfSPZ Vaccine induces strain-transcending T cells and durable protection against heterologous controlled human malaria infection. Proc Natl Acad Sci USA 114: 2711–2716.
Sissoko MS et al.2017. Safety and efficacy of PfSPZ Vaccine against Plasmodium falciparum via direct venous inoculation in healthy malaria-exposed adults in Mali: a randomised, double-blind phase 1 trial. Lancet Infect Dis 17: 498–509.
Jongo SA et al.2018. Safety, immunogenicity, and protective efficacy against controlled human malaria infection of Plasmodium falciparum sporozoite vaccine in Tanzanian adults. Am J Trop Med Hyg 99: 338–349.
Olotu A et al.2018. Advancing global health through development and clinical trials partnerships: a randomized, placebo-controlled, double-blind assessment of safety, tolerability, and immunogenicity of Plasmodium falciparum sporozoites vaccine for malaria in healthy Equatoguinean men. Am J Trop Med Hyg 98: 308–318.
- Search Google Scholar
- Export Citation
Olotu A 2018. Advancing global health through development and clinical trials partnerships: a randomized, placebo-controlled, double-blind assessment of safety, tolerability, and immunogenicity of. Am J Trop Med Hyg Plasmodium falciparumsporozoites vaccine for malaria in healthy Equatoguinean men 98: 308– 318.
Jongo SA et al.2019. Safety and differential antibody and T-cell responses to the Plasmodium falciparum sporozoite malaria vaccine, PfSPZ Vaccine, by age in Tanzanian Adults, Adolescents, Children, and Infants. Am J Trop Med Hyg 100: 1433–1444.
Jongo SA et al.2020. Increase of dose associated with decrease in protection against controlled human malaria infection by PfSPZ Vaccine in Tanzanian adults. Clin Infect Dis 71: 2849–2857.
Roestenberg M et al.2020. A double-blind, placebo-controlled phase 1/2a trial of the genetically attenuated malaria vaccine PfSPZ-GA1. Sci Transl Med 12 : eaaz5629.
Steinhardt LC et al.2020. Safety, tolerability, and immunogenicity of PfSPZ vaccine administered by direct venous inoculation to infants and young children: findings from an age de-escalation, dose-escalation double-blinded randomized, controlled study in western Kenya. Clin Infect Dis 71: 1063–1071.
- Search Google Scholar
- Export Citation
Steinhardt LC 2020. Safety, tolerability, and immunogenicity of PfSPZ vaccine administered by direct venous inoculation to infants and young children: findings from an age de-escalation, dose-escalation double-blinded randomized, controlled study in western Kenya. Clin Infect Dis 71: 1063– 1071.
Jongo SA et al.2021. Immunogenicity and protective efficacy of radiation-attenuated and chemo-attenuated PfSPZ vaccines in Equatoguinean adults. Am J Trop Med Hyg 104: 283–293.
Lyke KE et al.2021. Multidose priming and delayed boosting improve PfSPZ vaccine efficacy against heterologous P. falciparum controlled human malaria infection. Clin Infect Dis 73: e2424–e2435.
Oneko M et al.2021. Safety, immunogenicity and efficacy of PfSPZ vaccine against malaria in infants in western Kenya: a double-blind, randomized, placebo-controlled phase 2 trial. Nat Med 27: 1636–1645.
Sissoko MS et al.2021. Three dose regimen of PfSPZ Vaccine protects adult Malians against Plasmodium falciparum through an intense transmission season: a randomized, controlled phase I trial. Lancet Infect Dis (in Press).
Murphy SC, Duenas DM, Richie TL, Shah SK , 2020. Reexamining the categorical exclusion of pediatric participants from controlled human infection trials. Bioethics 34: 785–796.
Hoffman SL et al.2010. Development of a metabolically active, non-replicating sporozoite vaccine to prevent Plasmodium falciparum malaria. Hum Vaccin 6: 97–106.
Gomez-Perez GP et al.2015. Controlled human malaria infection by intramuscular and direct venous inoculation of cryopreserved Plasmodium falciparum sporozoites in malaria-naive volunteers: effect of injection volume and dose on infectivity rates. Malar J 14: 306.
Mordmüller B et al.2015. Direct venous inoculation of Plasmodium falciparum sporozoites for controlled human malaria infection: a dose-finding trial in two centres. Malar J 14: 117.
Sulyok M et al.2017. DSM265 for Plasmodium falciparum chemoprophylaxis: a randomised, double blinded, phase 1 trial with controlled human malaria infection. Lancet Infect Dis 17: 636–644.
Lell B et al.2018. Impact of sickle cell trait and naturally acquired immunity on uncomplicated malaria after controlled human malaria infection in adults in Gabon. Am J Trop Med Hyg 98: 508–515.
Murphy SC et al.2018. A randomized trial evaluating the prophylactic activity of DSM265 against preerythrocytic Plasmodium falciparum infection during controlled human malarial infection by mosquito bites and direct venous inoculation. J Infect Dis 217: 693–702.
Laurens MB et al.2019. Dose dependent infectivity of aseptic, purified, cryopreserved Plasmodium falciparum 7G8 sporozoites in malaria-naive adults. J Infect Dis 220: 1962–1966.
Metzger WG et al.2020. Ivermectin for causal malaria prophylaxis: a randomised controlled human infection trial. Trop Med Int Health 25: 380–386.
Murphy SC et al.2021. PfSPZ-CVac efficacy against malaria increases from 0% to 75% when administered in the absence of erythrocyte stage parasitemia: a randomized, placebo-controlled trial with controlled human malaria infection. PLoS Pathog 17: e1009594.
Ho M, Webster HK, Looareesuwan S, Supanaranond W, Phillips RE, Chanthavanich P, Warrell DA , 1986. Antigen-specific immunosuppression in human malaria due to Plasmodium falciparum. J Infect Dis 153: 763–771.
Orjih AU, Nussenzweig RS , 1980. Plasmodium berghei: suppression of antibody response to sporozoite stage by acute blood stage infection. Clin Exp Immunol 38: 1–8.
Ocaña-Morgner C, Mota MM, Rodriguez A , 2003. Malaria blood stage suppression of liver stage immunity by dendritic cells. J Exp Med 197: 143–151.
Shekalaghe S et al.2014. Controlled human malaria infection of Tanzanians by intradermal injection of aseptic, purified, cryopreserved Plasmodium falciparum sporozoites. Am J Trop Med Hyg 91: 471–480.
Schindler T et al.2019. Molecular monitoring of the diversity of human pathogenic malaria species in blood donations on Bioko Island, Equatorial Guinea. Malar J 18: 9.
Sulyok Z et al.2021. Heterologous protection against malaria by a simple chemoattenuated PfSPZ vaccine regimen in a randomized trial. Nat Commun 12: 2518.
Hodgson SH et al.2014. Evaluating controlled human malaria infection in Kenyan adults with varying degrees of prior exposure to Plasmodium falciparum using sporozoites administered by intramuscular injection. Front Microbiol 5: 686.
Achan J et al.2019. Serologic markers of previous malaria exposure and functional antibodies inhibiting parasite growth are associated with parasite kinetics following a Plasmodium falciparum controlled human infection. Clin Infect Dis 70: 2544–2552.
Kapulu MC, Njuguna P, Hamaluba MM , 2019. Controlled human malaria infection in semi-immune Kenyan adults (CHMI-SIKA): a study protocol to investigate in vivo Plasmodium falciparum malaria parasite growth in the context of pre-existing immunity. Wellcome Open Res 3: 155.
- Search Google Scholar
- Export Citation
Kapulu MC Njuguna P , Hamaluba MM 2019. Controlled human malaria infection in semi-immune Kenyan adults (CHMI-SIKA): a study protocol to investigate. Wellcome Open Res in vivo Plasmodium falciparummalaria parasite growth in the context of pre-existing immunity 3: 155.
Billingsley PF et al.2020. The Equatoguinean malaria vaccine initiative: from the launching of a clinical research platform to malaria elimination planning in Central West Africa. Am J Trop Med Hyg 103: 947–954.