Safety, Immunogenicity and Efficacy of Prime-Boost Vaccination with ChAd63 and MVA Encoding ME-TRAP against Plasmodium falciparum Infection in Adults in Senegal

• DOI: 10.1371/journal.pone.0167951
• Publication Date: 2016-12-16T19:56:41Z
• Authors: Victorine A. Mensah; Aly Gueye; Magatte Ndiaye; Nick J. Edwards; Danny Wright; Nicholas A. Anagn...; Massamba Syll; Amy Ndaw; Annie Abiola; Carly Bliss; Jules-François Gomis; Ines Petersen; Caroline Ogwang; Tandakha Dieye; Nicola K. Viebig; Alison M. Lawrie; Rachel Roberts; Alfredo Nicosia; Babacar Faye; Oumar Gaye; Odile Leroy; Egeruan B. Imoukh...; Katie J. Ewer; Philip Bejon; Adrian V. S. Hill; Badara Cisse
• Keywords: Vaccine efficacy

Malaria transmission is in decline some parts of Africa, partly due to the scaling up control measures. If goal elimination be achieved, additional measures including an effective and durable vaccine will required. Studies utilising prime-boost approach deliver viral vectors encoding pre-erythrocytic antigen ME-TRAP (multiple epitope thrombospondin-related adhesion protein) have shown promising safety, immunogenicity efficacy sporozoite challenge studies. More recently, a study Kenyan adults, similar that reported here, showed substantial against P. falciparum infection. One hundred twenty healthy male volunteers, living malaria endemic area Senegal were randomised receive either Chimpanzee adenovirus (ChAd63) as prime vaccination, followed eight weeks later by modified vaccinia Ankara (MVA) also booster, or two doses anti-rabies comparator. Prior follow-up, antimalarials administered clear parasitaemia then participants monitored PCR for infection weeks. The primary endpoint was time-to-infection with malaria, determined consecutive positive results. Secondary endpoints included adverse event reporting, cellular humoral meta-analysis combined parallel adults.We show this safe induces significant immunogenicity, peak T-cell response at seven days after boosting 932 Spot Forming Cells (SFC)/106 Peripheral Blood Mononuclear Cells(PBMC) compared 57 SFC/ 106 PBMCs group. However, not observed: 12 vaccinees became during intensive monitoring period 13 58 controls (P = 0.80). This trial confirms adults may rapidly assessed using efficient cost-effective clinical design. Further evaluation vectored candidate other settings age-de-escalation into main target age groups progress.