Search

BackgroundAdhesion of P. falciparum-infected erythrocytes (PEs) to placental chondroitin-4-sulfate (CSA) has been linked to severe placental malaria (PM) outcomes. Evidence strongly supports the VAR2CSA variant surface antigen mediating PEs CSA-binding phenotype as the leading candidate for a PM vaccine. This study was conducted to assess the safety and immunogenicity of 3 different dosages (20 µg, 50 µg and 100 µg) of the recombinant VAR2CSA protein (PRIMVAC), formulated with Alhydrogel or GLA-SE administered at days 0, 28 and 56.MethodsA randomised double-blind phase Ia/Ib dose-escalation vaccine trial was conducted in healthy adult women. Within 4 sequential cohorts, volunteers were randomised to 2 arms (PRIMVAC adjuvanted with Alhydrogel or GLA-SE) in the first phase conducted in France and then to 3 arms (PRIMVAC with Alhydrogel or GLA-SE or placebo) in Burkina Faso. Enrolled volunteers were observed for at least 1 hour following each vaccination then seen at 1 day and 7 days later for safety evaluations. Serious adverse events (SAE) were recorded throughout the study duration. Routine clinical laboratory safety analyses were performed prior to first injection and at each subsequent visit.ResultsA total of 68 subjects were recruited in the four study cohorts. No SAE was reported in any of the cohort A volunteers and enrolment in cohort B was started. A Data Safety Monitoring Board (DSMB) reviewed the safety data for cohorts A (20 µg) and B (50 µg) before the trial was initiated in Burkina Faso. The DSMB also reviewed the safety data in Burkina to authorise the progression from the cohort C (50 µg) to cohort D (100 µg). The last vaccination of the last subject occurred in September 2017.ConclusionThis was the first placental malaria vaccine phase Ia/b clinical trial conducted in France and Burkina Faso. No serious adverse events have been recorded. Preliminary safety and immunogenicity results will be presented.

Background Any development of a vaccine strategy or its implementation is based on a good knowledge of the biology of the pathogen and its temporal and spatial distribution. In the case of malaria, the main four species responsible for the disease though having a similar biological structure are not equally represented spatially due to factors such as environment and susceptibility of human to species. Methods In order to characterise a site for a future malaria vaccine implementation in terms of malaria prevalence and its species distribution, two cross sectional studies were conducted in October and March corresponding to the high and low malaria transmission season, respectively, in the Banfora Health District. A total of 1203 volunteers aged from 0.5 to 45 years consented to participate in the study. During each survey, after a brief physical examination, blood was taken from each volunteer by finger prick to perform thick and thin blood film examination. Blood smears collected were air dry and the thin film fixed with methanol. Dry smears were then stained with controlled PH Giemsa buffer solution and checked for malaria parasite using light microscope. Results Malaria prevalence was markedly high during high malaria transmission: 54.26% compared to low malaria transmission season 39, 40%. Plasmodium index was 46.8% with a gametocyte index of 11%. Main species present in the study area were P. falciparum, P. malariae and P. ovale. Species distribution was almost the same across the two seasons with P. falciparum being more prevalent compared to other species with respectively 97.8% and 98.7%. Conclusions P. falciparum, P. malariae and P. ovale are the three main species in the study area with almost the same distribution across the two seasons.