A booster shot of a malaria vaccine developed at the University of Oxford has shown durable and high protection in children, a study has shown, offering hope in the fight against the deadly disease.
Malaria, which is caused by parasites, is both preventable and curable. There were 241mn cases globally in 2020, according to the World Health Organization, which led to an estimated 627,000 deaths. Africa accounts for most cases and deaths, and children are particularly affected.
The findings of the mid-stage peer-reviewed study were published on Wednesday in The Lancet health journal. A total of 450 participants aged five to 17 months took part in the study in Burkina Faso, 409 of whom received a booster.
Participants were randomly assigned to three groups, with the first two receiving the R21 vaccine with an adjuvant — a substance that boosts the efficacy of jabs — at a high or low dose, yielding higher and lower efficacy, respectively. The third group received a rabies vaccine. Each child received a further dose of the same vaccine they had been given previously.
A booster dose of the vaccine showed efficacy as high as 80 per cent in one group, and 70 per cent in the other. Efficacy was calculated against clinical signs of malaria, scientists said, adding it met the WHO’s efficacy threshold of at least 75 per cent.
“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,” said Professor Adrian Hill, who heads Oxford university’s Jenner Institute research body and was a co-author of the paper.
Halidou Tinto, the trial’s principal investigator, said it was “fantastic [to] see such high efficacy again after a single booster dose”.
Oxford’s Katie Ewer, a co-author on the study, said it was “possible” that a second booster would not be needed, though it was too early to say. She added that the data looked “very solid” for participants in the study, but it might change with a broader population.
The vaccine is administered with Novavax’s Matrix-M adjuvant, and is licensed to the Serum Institute of India.
Oxford’s Hill said SII was “willing and able to make 200mn doses a year next year”, but he stressed the problem would be the logistics and deployment in each country. He added that Oxford and SII were looking to manufacture the vaccine directly in Africa, though this would not “happen in months”. He declined to give a precise price for the vaccine, which he said would be “a few dollars a dose”.
A previous analysis of the study showed efficacy of 77 per cent over 12 months.
The trial will continue for another two years to determine whether further booster doses will be necessary to retain protection. Results from a late-stage trial in 4,800 children are also expected later this year.
The WHO, which says the coronavirus pandemic has undermined efforts to prevent and manage the disease, gave broad backing to a GSK malaria vaccine for children late last year. However, fewer doses — 18mn over the next three years — are available than the jab developed by Oxford. Hill said the university would apply for WHO approval this month.
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