Malaria jab trial raises hope for mass rollout

A booster dose of a new malaria vaccine by Britain’s Oxford University maintains a high level of protection against the mosquito-borne parasitic disease, according to its makers.

Trial results released on Thursday suggested the R21/Matrix-M vaccine could represent a turning point in the fight against a disease that killed 627,000 people – mostly African children – in 2020 alone, expressing hopes the cheap jab could be produced on a large scale in a matter of years.

Last year, a different vaccine produced by British pharmaceutical giant GSK became the first to be recommended for widespread use against malaria by the World Health Organization (WHO) and has since been administered to more than a million children in Africa.

However, research has found that the effectiveness of GSK’s Mosquirix vaccine is about 60 per cent, and significantly wanes over time even with a booster dose.

Oxford’s R21/Matrix-M vaccine, meanwhile, was found to be 77 per cent effective at preventing malaria in research published last year – the first time the WHO’s roadmap goal of 75 per cent had been met.

For the research, 450 children aged five to 17 months in Burkina Faso were given three doses in 2019.

Different doses

They were split into three groups, two receiving different doses of the Matrix-M adjuvant, a vaccine ingredient patented by Novavax and also used in the United States biotech firm’s Covid-19 jab. The third control group received a rabies vaccine.

Before the 2020 rainy season – when malaria cases surge – 409 children returned to get a booster shot. For the group that received the higher dose of adjuvant, the booster rose the protection level to 80 per cent, according to the results of a phase 2b trial published in The Lancet Infectious Diseases journal on Thursday. The lower dose had 70 per cent efficacy.

And crucially, the booster returned antibody levels to a similar level seen after the first round of doses, the study said.

“It is fantastic to see such high efficacy again after a single booster dose,” said the study’s lead investigator, Halidou Tinto, of the Burkina Faso health research institute IRSS.

Tinto, who was involved in trialling both malaria vaccines, said GSK’s vaccine had an optimal efficacy of about 60 per cent. “So I can confirm that R21 is doing much better,” he told a news conference.

Oxford vaccinologist and study co-author Adrian Hill said the vaccine meant, “we really could be looking at a very substantial reduction in that horrendous burden of malaria, deaths and disease in the coming years, certainly by 2030”.

A 70 per cent reduction in deaths from malaria could be feasible in that time, he said, partly because of the vast number of vaccine doses that could be quickly produced.

Vaccine manufacturer

Oxford has partnered with the world’s largest vaccine manufacturer, the Serum Institute of India. The institute is “willing and able to manufacture 200 million doses a year starting next year”, Hill said.

The six to 10 million doses that GSK can produce a year is “not enough for 40 million children who need four doses in the first year”, Hill added.

Results from a phase three trial involving 4,800 participants across four countries are expected later this year, which could potentially lead to approval.

Azra Ghani, an epidemiologist at Imperial College London not involved in the research, welcomed the results, saying it was “particularly encouraging” that the booster dose restored protective antibodies.

Gareth Jenkins, of the charity Malaria No More UK, said the results were “another encouraging signal that, with the right support, the world could end child deaths from malaria in our lifetimes”.

Developing a malaria vaccine has been far more difficult than a Covid-19 shot because the disease-carrying parasite, Plasmodium, is such a complex organism.

Different technology

The R21 shot – developed by the Jenner Institute behind the Oxford-AstraZeneca jab, but using different technology – targets the parasite during the earliest stages of its life cycle.

Prof Katie Ewer, a professor of vaccine immunology at the Jenner Institute said this would “stop people getting sick in the first place”.

“R21 is trying to block the parasites before they get to your liver and start an infection,” she added.  Last year, early phase two trials found R21 was 77 per cent effective in 450 children in Burkina Faso. The latest results are from a phase 2b trial conducted at the country’s Clinical Research Unit of Nanoro/Institut de Recherche en Sciences de la Santé (IRSS), where 450 children aged five to 17 months were randomly assigned to three groups.                              

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