This study aims to test the safety and efficacy of six new malaria vaccines - AdCh63 AMA1, MVA AMA1, AdCh63 MSP1, MVA MSP1, AdCh63 ME-TRAP \& MVA ME-TRAP. These vaccines consist of inactivated viruses which have been modified - so they cannot reproduce (replicate) in humans, and also to include genetic material (genes) for malaria proteins which are expressed by the malaria parasite during both liver and blood stage infection. The vaccines are designed to stimulate an immune response to these malaria proteins (immunogenicity describes the nature and magnitude of this immune response) and thus provide protection against malaria infection. The protective efficacy of vaccines will be evaluated by challenging a small number of volunteers who have received the vaccines with malaria infection from the bites of infected mosquitos(sporozoite challenge).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
52
1 dose of AdCh63 MSP1 5 x 1010 vp intramuscularly and 1 dose MVA MSP1 2.5 x 108 pfu intramuscularly 8 weeks later (range 6-12 weeks) followed by sporozoite challenge 12-28 days later
1 dose of AdCh63 AMA1 5 x 1010 vp intramuscularly and 1 dose MVA AMA1 2.5 x 108 pfu intramuscularly 8 weeks later (range 6-12 weeks) followed by sporozoite challenge 12-28 days later
1 dose of AdCh63 AMA1 5 x 1010 vp intramuscularly and 1 dose AdCh63 MSP1 5 x 1010 vp intramuscularly co-administered into separate arms followed 8 weeks later (range 6-12 weeks) by 1 dose of MVA AMA1 2.5 x 108 pfu intramuscularly and 1 dose MVA MSP1 2.5 x 108 pfu intramuscularly co-administered into separate arms (but the same arm as the corresponding AdCh63 vaccine) followed by sporozoite challenge 12-28 days later.
1 dose of AdCh63 MSP1 5 x 1010 vp intramuscularly and 1 dose AdCh63 ME-TRAP 5 x 1010 vp intramuscularly co-administered into separate arms followed 8 weeks later (range 6-12 weeks) by 1 dose of MVA MSP1 2.5 x 108 pfu intramuscularly and 1 dose MVA ME-TRAP 2 x 108 pfu intramuscularly co-administered into separate arms (but the same arm as the corresponding AdCh63 vaccine) followed by sporozoite challenge 12-28 days later.
Non-vaccinated controls for sporozoite challenge
Hospital for Tropical Diseases Mortimer Market
London, United Kingdom
Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford
Oxford, United Kingdom
Wellcome Trust Clinical Research Facility, University of Southampton
Southampton, United Kingdom
Safety and efficacy of vaccine
To assess if volunteers who receive the novel vaccine candidates; AdCh63 MSP1, MVA MSP1, AdCh63 AMA1, MVA AMA1, AdCh63 ME-TRAP and MVA ME-TRAP in heterologous prime boost regimens are protected wholly or partially against malaria infection in a sporozoite challenge model. This will be determined by noting the number of subjects who develop malaria infection and the time in hours between exposure and parasitaemia as detected by thick-film blood smear compared with controls. To assess the safety of the immunisation regimens alone and during co-administration.
Time frame: Up to 18 months
Immunogenicity of vaccine
To assess immunogenicity of the vaccine regimes by measuring IFN-γ ELISPOT, flow cytometry and antibody responses to MSP1, AMA1 and ME-TRAP antigens before and after malaria infection. If there is evidence of partial or complete protection, we will explore immunological correlates of protective immunity.
Time frame: Up to 18 months
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