25/04/23

Malaria vaccine adoption pre-empts WHO green light

This anopheles gambiae mosquito is obtaining a blood meal as it
Malaria is transmitted to humans via female mosquitoes of the genus Anopheles.

Speed read

  • Ghana and Nigeria approve new malaria vaccine for young children
  • Nigeria accounts for more than a quarter of world’s malaria deaths
  • Other African countries expected to follow as WHO reviews trial data

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[EDO, NIGERIA] The approval of the R21/Matrix-M malaria vaccine by Ghana and Nigeria is the first time a major malaria intervention has been adopted without World Health Organization (WHO) qualification and could greatly reduce child deaths in Africa, say disease experts.

Africa accounts for around 95 per cent of all malaria cases and four out of five malaria deaths in the region occur in children under five. Progress in fighting the disease has stalled in recent years, health experts say, even before the COVID-19 pandemic.

In 2021, the WHO approved drugmaker GSK’s RTS,S malaria vaccine – the first ever vaccine against a parasitic disease – after it cut infections by around 40 per cent in a large-scale, human trial. 

Although this was a breakthrough, the vaccine’s efficacy is considered low and its use is limited by high production costs.

This month (13 April), Ghana became the first country in the world provisionally to approve the more effective R21/Matrix-M malaria vaccine, developed by the UK’s University of Oxford, for use in children aged five months to three years. 

Last week (17 April), Nigeria followed suite and approved the vaccine, which is still awaiting publication of final stage trial data.

“The vaccine needs to be rolled out into the countries and the efficacy needs to be shown in real life rather than just in trial conditions.”

Jaishree Raman, National Institute for Communicable Diseases, South Africa

“After so many years, it is really encouraging to have two possible vaccines,” said Jaishree Raman, who heads the malaria research laboratory at South Africa’s National Institute for Communicable Diseases.

“It is definitely a step forward, even if they are partially effective.” 

The WHO says a prequalification process is underway for the R21/Matrix-M vaccine, with a working group of expert advisors reviewing safety and efficacy data from the ongoing phase three trial before making any recommendation. 

Raman says she was impressed by the two countries’ decision to approve the vaccine, ahead of official WHO authorisation. 

“It is something that we haven’t seen before for malaria,” she told SciDev.Net.

“It gives the possibility that, moving forward, African countries won’t constantly look to the WHO for prequalification and approval.”

In 2021, Nigeria accounted for 27 per cent of the world’s 247 million cases of malaria, according to the WHO’s 2022 report on the disease.  

Around half of all malaria deaths occurred in just four countries: Nigeria (31 per cent), the Democratic Republic of Congo (13 per cent), Niger (four per cent) and Tanzania (four per cent), the report says. 

In Ghana, about 20,000 children a year die from malaria, a study says. 

‘Safe for use’

The Ghana Food and Drugs Authority says the vaccine’s approval resulted from an extensive review of its quality, safety and efficacy using data from the continuing stage three trial in Burkina Faso, Kenya, Mali and Tanzania.

Mojisola Christianah Adeyeye, director-general of Nigeria’s National Agency for Food and Drug Administration and Control, while granting approval, stressed the need to expand the trial to further assess possible adverse effects.  

The vaccine previously underwent trials in the UK on adults as well as in Kenya on babies, young children and adults. 

Mehreen Datoo, an infectious diseases expert at Oxford University’s Jenner Institute who was part of the team that developed the vaccine, told SciDev.Net that the first phase of the clinical trial showed that the vaccine was safe enough for use. 

In a subsequent phase two trial conducted in Nanoro, Burkina Faso, 450 five to 17-month-old children were assigned into three groups, with the first two groups receiving a low or a high dose of the R21/Matrix-M malaria vaccine while the third group received a rabies vaccine. 

The children were given three doses of the vaccines four weeks apart before the malaria season. One year later, they received a booster shot of the same vaccine.

The researchers reported 77 per cent efficacy in the group that received the high dose, with 80 per cent efficacy after receiving the booster shot. 

“All the adverse events that were thought to be related to the vaccine were mild and self-limiting and they resolved within a couple of days of the vaccine being given,” said Datoo, a co-author of the study. 

What next?

At least ten other African countries’ regulatory authorities are reviewing the trial data and many are expected to approve the vaccine in the coming weeks, Reuters news agency reported, citing a WHO official.

Adar Poonawalla, chief executive of the Serum Institute of India (SII), which is manufacturing the vaccine, said: “We remain steadfast in our commitment to scaling up production of the vaccine to meet the needs of countries with high malaria burden and to support global efforts towards saving lives.”

Datoo told SciDev.Net that Oxford University’s partnership with SII aimed to produce affordable malaria vaccines for African children.

“The R21/Matrix-M malaria vaccine is a low-dose vaccine that can be manufactured at a mass scale and modest cost, enabling as many as hundreds of millions of doses to be supplied to African countries which are suffering a significant malaria burden,” a statement by the university said. 

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Raman says that if the vaccine proves as effective as trials have so far indicated, it could have a major impact on reducing the malaria burden in children, and get countries much closer to eliminating malaria in the near future.

“But there are obviously a number of steps that need to fall into place before that can happen,” she cautioned. 

“The vaccine needs to be rolled out into the countries and the efficacy needs to be shown in real life rather than just in trial conditions.” 

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.