Malaria killed about 640 thousand people in 2020, largely young children in Africa. Rapid recent progress has led to two anti-sporozoite vaccine developers planning WHO prequalification applications in 2022. These include the new high efficacy R21/Matrix-M vaccine, to be supplied at the required large scale, and led by partners in this consortium. In parallel, recent progress with transmission-blocking malaria vaccines has led to substantial efficacy in a first direct skin feeding field trial. This opens up the prospect of a two-stage vaccine targeting both sporozoites and sexual-stage parasites that should have a major impact on malaria transmission, thereby enabling regional elimination and ultimate eradication. We propose here to develop such a vaccine assessing both established virus-like particle (VLP) vaccines in potent saponin adjuvants and also exciting new thermostable mRNA vaccines expressing the parasite antigens now showing high efficacy. Importantly, we will adopt new VLP design technologies, e.g. SpyCatcher bonding, that allow bivalent antigen display, to enable a single vaccine to protect against both the Plasmodium falciparum parasite, which causes most deaths, and the more widespread Plasmodium vivax parasite. A lead vaccine candidate will be down-selected based on well-studied pre-clinical efficacy models and induction of functional transmission-blocking antibodies, prior to GMP manufacture and a clinical trial in year 4. The consortium brings together academics, non-profits and a wide range of companies with both leading technologies and access to small and very large scale GMP manufacturing capacity. This programme builds on the recent success of several partners in the R21/Matrix-M programme and aims to accelerate the malaria eradication agenda by providing the first vaccine to tackle both major malaria parasite species, and confer both individual and community protection on the way to eradication.

Plasmodium vivax is the most widespread human malaria with 2.5 billion people living at risk in South America, Oceania and Asia. The revised Malaria Vaccine Technology Roadmap to 2030 recognises the severity of P. vivax malaria, calling for a vaccine intervention to achieve 75% efficacy over two years, now equally weighted with P. falciparum. However, if this ambition is to be realised, new and innovative approaches are urgently required to accelerate next-generation vaccine research and development, whilst the few known candidate antigens need to undergo early-phase clinical assessment. Here, we build on exciting breakthroughs in P. vivax vaccine research, recently pioneered in Europe, including new transgenic parasite technologies for functional assay development and production of a parasite clone that is safe for use in controlled human malaria infection (CHMI) clinical models. The Objectives of OptiViVax will now integrate ambitious multi-disciplinary scientific and clinical approaches around the parasite’s lifecycle and will use our increased knowledge of P. vivax immuno-biology to further develop next-generation vaccines with improved efficacy. We will diversify the portfolio of new antigens ready for clinical testing by reverse vaccinology and diversify their delivery with new platforms and adjuvants developed using sustainable and improved GMP bio-manufacturing know-how. In parallel, the efficacy of known leading antigens will be benchmarked for the first time using innovative design of clinical studies and CHMI models making these lead candidate vaccines ready for future field trials. Improved preclinical functional assays, using state-of-the-art transgenic parasite lines, will also allow for mechanisms of antibody-mediated protection to be deciphered. The availability of new functional assays and human challenge models will underpin the future framework for informed decision making by the clinical vaccine community, policy makers, funders and regulators.