The new R21/Matrix-M malaria vaccine, developed by The University of Oxford and manufactured by The Serum Institute of India, has been granted its first “full national licensure” by Ghana’s Food and Drugs Authority (FDA Ghana). The vaccine is contributing to the global fight against malaria, of which there are 241 million cases and an estimated 627,000 deaths globally in 2020. In Ghana alone, over 5 million malaria cases were confirmed in 2021, which marks the approval of the new vaccine as an important move by the Ghanaian government to tackle the malaria crisis. So how does this vaccine work? Is it truly effective? And what is the significance of an African country being the first to approve this vaccine?
How does the vaccine work?
When a mosquito carrying the malaria parasite bites an individual, the parasite enters the bloodstream and evolves into different forms over its life cycle. The first form of the malaria parasite is the ‘sporozoite’ which the R21/Matrix-M vaccine targets to prevent the development of malaria.
Vaccines help build immunity against infections and typically achieve this by introducing antigens to our immune cells. Antigens are pieces of a pathogen (e.g. malaria parasite) that our body recognises and learns to respond to. The R21/Matrix-M vaccine works by delivering parts of the sporozoite proteins (i.e. the antigen) that are also fused with hepatitis B virus fragments to trigger an immune response against future malaria infection.
The Matrix-M component of the R21/Matrix-M vaccine, called the “adjuvant”, seeks to amplify this immune response by triggering ‘antigen-presenting cells’ to flow towards the injection site. This means that the immune system will be strongly activated to combat malaria infection and the vaccine more potent with long-lasting effects.
How Effective is the Vaccine?
When a new drug/treatment is developed, its efficacy (i.e. performance under ideal and controlled conditions) must be rigorously tested through 4 phases of clinical trials, with each phase increasing the number of study participants included.
A phase 1/2b trial of the R21/Matrix-M vaccine was conducted in children aged 5-17 months old in Burkina Faso, whereby a series of vaccinations were administered before or at the start of the malaria season, to assess the efficacy of the vaccine in preventing the occurrence of malaria. The trial, which was published in The Lancet Infectious Diseases, discovered the vaccine’s efficacy to be 71% (low adjuvant dose) and 77% (high adjuvant dose).
Twelve months after the initial vaccination, they administered booster doses and monitored the efficacy of the booster doses over another 12 months. They discovered an efficacy of 70% (low adjuvant dose) and 80% (high adjuvant dose). These findings, therefore, indicate that the R21/Matrix-M vaccine is the first to meet the World Health Organisation’s (WHO) target for a malaria vaccine to have at least 75% efficacy by 2030.
Although data from a phase 3 trial has not yet been publicly published, the phase 3 results obtained so far suggest a similar efficacy/performance of the R21/Matrix-M vaccine as in the phase 2 trial. This is according to Professor Adrian Hill, the director of the Jenner Institute at the University of Oxford, which is where the vaccine was developed. Upon assessing the trial data, FDA Ghana decided to license the use of the vaccine in children aged 5 to 36 months.
What is the significance of this approval by Ghana?
Ghana’s approval of the R21/Matrix-M vaccine is significant because it has come before the WHO’s approval of the vaccine. It has now been reported that Nigeria, the world’s most malaria-affected country accounting for 27% of global cases and 32% of global deaths, has also granted provisional approval to the vaccine, making it the second country to do so. The regulatory authorities of 10 other African countries are also reviewing the data from the trials and more approvals of the vaccine are expected in the coming weeks. This highlights the urgency to tackle a disease in which 96% of its cases and deaths each year occur in Africa, with children under 5 years of age being the most affected.
The move by Ghana has also been tagged as ‘unusual’ in an article by Reuters. This is because many African countries lack efficient drug regulatory systems, hence “African countries that do not have extensive resources for drug regulation have previously relied on the U.N. agency to initially review new medicines”.
The article states that this move signifies that African countries desire to “exert their own pharmaceutical oversight” especially after the COVID-19 crisis revealed inequities in vaccine supply. The article also suggests that “African countries may want to limit their reliance on Western governments and companies by manufacturing life-saving drugs in the continent” which aligns with new reports on alliance talks between The Serum Institute of India and a Ghanaian producer, DEK Vaccines Ltd, to produce doses of R21 within Ghana in the long term.
Overall, the move made by Ghana to approve the R21/Matrix-M vaccine is a significant one that appears to be paving the way for other African countries to approve the vaccine also. A phase 3 trial assessing the safety and efficacy of the R21-Matrix-M vaccine in 4,800 children across 5 sites, in East and West Africa, is ongoing and the results are expected to be released this year. The widespread use of the vaccine may depend on the results of this larger trial.
By Success Fabusoro