Malaria continues to be one of the most serious public health problems in many parts of the world, particularly sub-Saharan Africa where children under five are at higher risk of developing this disease, both in terms of morbidity and mortality. In the past, global efforts have led to remarkable progress in the control and prevention of malaria, through the use of insecticide-treated bed nets, as well as antimalarial drugs. However, vaccines remain a prominent weapon against this dreaded disease. This article discusses the place of malaria vaccines in child malaria prevention, by highlighting current progress and the prospects for its use in the prevention of the disease.
The Burden of Malaria in Children
Malaria is a parasitic disease. Anopheles mosquitoes transmit the disease, which is primarily caused by Plasmodium falciparum, with Plasmodium vivax as the second most common cause. Symptoms include fever, chills, and flu-like illness, which can progress to anemia, cerebral malaria, and, in severe cases, death.
- Incidence: In 2022, according to the World Health Organization (WHO), there were 247 million cases of malaria worldwide with a large proportion in the under-five age group.
- Mortality: Mortality rates are high, especially in children – with and without treatment – and in those with poorly controlled disease. In endemic areas, malaria is a major cause of childhood death.
The Role of Vaccines in Malaria Prevention
The famed success of vaccination in halting a range of infectious diseases has prompted optimism that vaccines, too, can diminish the burden of malaria – notably in particularly susceptible children. The cortical projection of the Plasmodium-specific compartment Neurons from various regions, including the cortex, send collaterals into the blood vessel, creating an immunological synapse containing Plasmodium-specific antigens along the length of the vessel (green). The immune synapses are clearly visible on the cell body, indicated by arrows. The regions of neuronal cell bodies stained for blood vessel antigens appear in red, while immune-synapse antigens are shown in green. The merging of these stains highlights the location of synapses on the neuronal cell bodies in yellow.
Current Malaria Vaccines
RTS, S/AS01 (Mosquirix)
- Malaria vaccine under development: The most advanced malaria vaccine to date, called RTS, S, is made by GlaxoSmithKline in collaboration with the PATH Malaria Vaccine Initiative. It attacks Plasmodium falciparum and is now entering late-stage clinical trials.
- Approval and Rollout: 2021: RTS, S WHO paves the way for use in children in areas of highest risk: 2022: first country using RTS, S as part of routine immunization. 2023: second country joins the malaria-prevention game.
- Efficacy: Clinical trials on RTS, S suggests it has about 30 percent efficacy generally, meaning it cuts malaria cases by approximately that percent, and around 39 percent efficacy for severe malaria in young children.
R21/Matrix-M
- Development: The Oxford/AstraZeneca R21/Matrix-M vaccine candidate has garnered considerable attention as an injection vaccine in early-stage clinical trials.
- Efficacy: In recent trials, the efficacy of R21/Matrix-M was 77 percent in preventing malaria in children. This is a great improvement on previous vaccines.
- Status: It is now in late-stage trials and undergoing regulatory review so it will hopefully be broadly available within a year.
Challenges in Malaria Vaccination
Vaccine Coverage and Access
- Distribution: A major challenge with malaria vaccines – and with other vaccines targeting diseases that are common in poor and remote places – is ensuring equitable access. Infrastructure, logistics, and supply chain challenges create difficulties in getting vaccines to difficult-to-reach populations.
- Acceptance: Barriers to uptake, such as vaccine hesitancy or misinformation, can arise. Public health education and community engagement can help ensure higher vaccination coverage in a community.
Vaccine Efficacy and Duration
- Partial protection: current malaria vaccines provide only partial protection, which requires complementation with insecticide-treated nets and antimalarial drugs.
- Duration of immunity is a crucial unknown for all malaria vaccines in development. Researchers are actively investigating how long vaccine protection lasts and whether booster doses will be necessary.
Cost and Funding
Affordability: The price of developing, producing, and distributing malaria vaccines can be high. Vaccines need to be priced in a way that can be funded by philanthropy from international organizations, governments, and public-private partnerships.
Future Prospects in Malaria Vaccine Development
Next-Generation Vaccines
- Research and Innovation: Scientists are investigating different ways of improving vaccination against malaria, including combination vaccines, novel adjuvants, and vaccines that target other stages of the parasite’s life cycle.
- Genetic and genomic advances: Genetic and genomic advances are making sense of malaria parasites and potentially putting more effective vaccines on the development horizon.
Integration with Other Malaria Control Strategies
- Holistic Approach: Apart from the vaccine, vaccines should be incorporated within the existing malaria control interventions such as vector control, case management, and community education.
- Synergy: The use of vaccines in combination with other preventive interventions can improve the overall efficacy of interventions and contribute to the long-term goal of malaria elimination.
Global Collaboration and Funding
- Partnerships: To advance malaria vaccine development and distribution, ongoing collaboration among governments, international organizations, the private sector, and research institutions is essential.
- Investment: There is a critical need for increased investment in malaria research and vaccine development, as well as expanded trials for new vaccine candidates. We must accelerate progress to meet these goals for global health.
Vaccines, as an intervention, have the potential to markedly reduce the pediatric malaria burden and to aid malaria elimination efforts. Although current vaccine candidates such as RTS, S, and R21/Matrix-M show great promise, more can be done. Vaccines can only reach their full potential by addressing gaps in vaccine access, efficacy, and cost.
Meanwhile, the search for new-generation malaria vaccines, coupled with their use alongside other tools will be important to overcome this disease. International collaboration and sustained funding – alongside universal healthcare – will be essential if we are to deliver the promise of malaria vaccination for those who need it most.
This reinforces the options by investing in malaria vaccines and supporting other measures that ensure the overall prevention of the disease. Human-centered approaches to control this pathogen, all supported through financial donations, are possible in a lifetime to reduce child mortality and improve health in malaria-endemic regions. The prospect for malaria prevention in the future is bright, and research on vaccines will continue as long as there’s a life-threatening disease.
