Malaria vaccines for children: and now there are two.

In 2021, nearly half of the world's population lived at risk from malaria, with over 600 000 deaths annually, of which over 95% occur in the WHO African region and 80% of these in children younger than 5 years.1 WHO recommends several preventive and curative interventions that, when used together, can greatly reduce malaria illness and death, including effective vector control, chemoprevention, and prompt diagnosis and treatment, and since October, 2021 malaria vaccines, the first of which is RTS,S/AS01.2 Malaria, specifically Plasmodium falciparum, is the first human parasite for which vaccination has proved possible. Over 40 years of vaccine development took place since the identification of the circumsporozoite antigen as a functionally important antigen. A key finding in 2021 was the successful demonstration of programmatic feasibility, effectiveness, and safety of RTS,S/AS01 in very large pilot implementations in three African countries.2 Demand for malaria vaccines is unprecedented, with 18 countries already approved for Gavi, the Vaccine Alliance support for vaccine introduction in 2024. However, supply of RTS,S/AS01 is severely constrained, with only 18 million doses available between 2023 and 2025, and the annual demand is anticipated to be around 80–100 million doses.3 Inventors at the University of Oxford (Oxford, UK), in partnership with the Serum Institute of India (Pune, India), have now developed a second, circumsporozoite-based vaccine similar in construct to RTS,S/AS01, known as R21/Matrix-M. The Serum Institute of India has a track record of supplying other WHO-recommended vaccines at very large scale, at relatively low cost, and of meeting WHO's prequalification standards on vaccine quality, safety, and efficacy. Like RTS,S/AS01, the R21/Matrix-M vaccine targets the circumsporozoite antigen. R21/Matrix-M is formulated with a saponin-based adjuvant, Matrix-M, which is distinct from the AS01 adjuvant of RTS,S.