A booster dose of the candidate malaria vaccine has maintained a high level of protection against the disease and continued to meet the World Health Organisation’s (WHO) specified percent efficacy goal, researchers have disclosed.
Researchers from the University of Oxford and their partners last week reported new findings from their phase 2b trial following the administration of a booster dose of the candidate malaria vaccine, R21/Matrix-M – which previously demonstrated high-level efficacy of 77 percent over the 12 months in young West African children in 2021.
In their findings which were reported in The Lancet Infectious Diseases, they found that a vaccine booster dose at one year following a primary three-dose regime maintained high efficacy against malaria, and continued to meet WHO’s Malaria Vaccine Technology Roadmap goal of a vaccine with at least 75 percent efficacy.
The authors report from a Phase IIb randomised, controlled, double-blind trial conducted at the Clinical Research Unit of Nanoro (CRUN) / Institut de Recherche en Sciences de la Santé (IRSS), Burkina Faso. A total of 450 participants aged five to 17 months were recruited from the catchment area of Nanoro, with 409 receiving the booster.
The researchers report a vaccine efficacy of 80 percent in the higher-dose adjuvant group, and 70 percent in the lower dose adjuvant group, over 12 months of follow-up. Antibody levels were restored to similar levels as those following the primary vaccinations 28 days after the booster doses were administered. No serious adverse events related to the vaccine were noted.
Halidou Tinto, a professor in parasitology, regional director of IRSS in Nanoro, and the trial principal investigator, said, “It is fantastic to see such high efficacy again after a single booster dose of vaccine. We are currently part of a large phase III trial aimed at licensing this vaccine for widespread use next year.’
Adrian Hill, a professor, at the University of Oxford’s Jenner Institute, and Lakshmi Mittal and family professor of vaccinology, and co-author of the paper, said: “We are delighted to find that a standard four dose immunisation regime can now, for the first time, reach the high efficacy level over two years that has been an aspirational target for malaria vaccines for so many years.”
The R21/Matrix-M malaria vaccine candidate created by the University of Oxford includes Novavax’ proprietary saponin-based Matrix-M adjuvant and is licensed to Serum Institute of India.
The trial- funded by the EDCTP2 programme supported by the European Union (grant number RIA2016V-1649-MMVC) as well as the Wellcome Trust and NIHR Oxford Biomedical Research Centre – has been extended for another two years to assess if further booster doses will be necessary to maintain high efficacy over time.
Results from the key ongoing Phase III licensure trial to assess large-scale safety and efficacy in 4,800 children aged five to 36 months across four African countries, are also expected later this year.
“Today’s R21 vaccine results from Oxford’s renowned Jenner Institute are another encouraging signal that, with the right support, the world can end child deaths from malaria,” Gareth Jenkins, director of advocacy at Malaria No More UK said.