Malaria, caused by Plasmodium falciparum parasites, is a leading cause of death in children under five in many parts of Africa. Blood-stage malaria – when the parasite infects red blood cells – causes symptoms of the disease like fever and chills, and can lead to severe, life-threatening complications like anaemia and organ failure.
The study has been run by scientists at the University of Oxford in collaboration with the Clinical Research Unit of Nanoro (CRUN) at the Institut de Recherche en Sciences de la Santé (IRSS) in Burkina Faso, the London School of Hygiene and Tropical Medicine (LSHTM) in the UK and the National Institute of Health (NIH) in the USA, with support from other partners including the Serum Institute of India Pvt. Ltd, Novavax and ExpreS2ion Biotechnologies ApS.
The study team tested the safety and efficacy of the RH5.1/Matrix-MTM blood-stage malaria vaccine candidate in children aged 5 to 17 months in Nanoro Burkina Faso, following positive phase one results in Tanzanian adults and children. Over 360 children were enrolled in the study in 2023 and divided into two groups: one received three doses of the RH5.1/Matrix-MTM and the other three doses of a rabies vaccine as control. Neither the participants, their families nor the study teams knew who received which vaccine.
The results, published today in The Lancet Infectious Diseases, showed the vaccine was well tolerated with no safety concerns. Children who received the vaccine developed high levels of antibodies against the parasite, especially those who received their vaccine doses at 0, 1 and 5 months rather than at 0, 1 and 2 months. This group importantly achieved 55% effectiveness in preventing clinical malaria over a 6-month period. Alongside this, within the group of children who did develop clinical malaria, a proportion showed very high levels of parasites in their blood. Notably, the vaccine also demonstrated over 80% efficacy against these higher levels of malaria parasites, suggesting this vaccine could prevent severe cases of the disease in children in a real-world setting. These findings will now be explored further in future clinical trials.
Read the full story on the Department of Paediatrics website.