The results from a WHO pilot points to more countries in sub-Saharan Africa receiving the world’s first malaria vaccine.
In October of last year, the World Health Organization (WHO) recommended the use of RTS,S malaria vaccine among children living in regions with moderate to high transmission. WHO’s recommendation was based on a pilot conducted in Malawi in April 2019 which found the vaccine safe and effective. Since then, more than 1 million children in Malawi, Ghana, and Kenya have received one or more doses of the world’s first malaria vaccine. The WHO recently added the vaccine to their consolidated malaria guidelines. Moreover, the health body aims to expand its rollout to other sub-Saharan African countries.
In December of last year, the global vaccine alliance, Gavi, approved an investment of $155 million for the vaccine’s rollout. The funding will help in the introduction, procurement and delivery of the vaccine for Gavi-eligible countries in sub-Saharan Africa. According to John Bawa at Program for Appropriate Technology in Health (PATH), Gavi is currently paying 80% of the vaccine cost for some countries. While the government pays the remaining 20%.
In a recent webinar, Bawa stated that countries like Zambia, Nigeria, and Mozambique could soon receive the vaccine as part of an expanded distribution scheme. The WHO estimates that widespread deployment of the vaccine can help save the lives of an additional 40,000 to 80,000 African children each year.
30% Reduction in Hospital Admissions
RTS,S is a first-generation vaccine available under the brand name, Mosquirix. Not only is it the world’s first malaria vaccine but also the first vaccine against a parasite in humans. The vaccine is a result of 30 years of research and development. It is designed to prevent the Plasmodium falciparum parasite from infecting liver cells and causing disease symptoms. The recommended dosage is a schedule of 4 doses in children, starting at 5 months of age.
Since 2019, the vaccine has been administered as part of childhood vaccination in three country-led pilots. The malaria vaccine coverage has significantly improved in these regions. In Malawi, it increased from 88% in 2020 to 93% in 2021, in Ghana from 71% to 76%, and in Kenya, it increased from 69% to 83%. Thus, demonstrating a high community demand and capacity for childhood vaccination platforms.
As per the findings from the pilots, the vaccine showed a strong safety profile and good feasibility. It caused a 30% reduction in admissions for severe malaria, even in areas deploying insecticide-treated mosquito nets (ITNs). Moreover, the vaccine did not have any negative impact on the use of ITNs, other childhood vaccinations, or health-seeking behaviour for other febrile illnesses. Instead, it provided added protection to those not using any preventive measures. According to WHO, the vaccine reached more than two-thirds of children not sleeping under a bed net.
Currently, the maximum vaccine production capacity stands at 15 million doses per year. However, it is estimated to exceed 80 million doses annually.
Other Malaria Vaccine Candidates in the Works
In recent years, the global decline in malaria cases has stalled. In some high-burden countries, health officials have actually reported a reversal of progress. This is partly due to increasing insecticide resistance among mosquitoes, failed vector control strategies, the emergence of drug-resistant malaria, and several other factors. Therefore, researchers are working on developing more tools that can help prevent the infection from claiming more lives. The vaccine plays a huge role in reducing the disease burden. However, one candidate is not enough.
There are currently multiple vaccine candidates in the pipelines. One of them is the Sanaria vaccine. Based on a chemoprophylaxis approach, the vaccine combines live parasites with antimalarial drugs. According to phase 1 clinical trials, the vaccine provided long-lasting protection against the parasite. A phase 2 trial is currently underway in Mali.
Another candidate, the Matrix-M has also shown promising results. Developed by Oxford University’s Jenner Institute, the vaccine underwent a clinical trial in Burkina Faso among 450 children. The children received three doses, a month apart, and then a fourth dose after a year. Only 29.5% of children in the low dose group and 26% of children in the high dose group contracted malaria, compared to 71.4% in the control group. Thus, revealing the vaccine as 77% effective.
Other than vaccines, researchers are also working on better vector control strategies that can help control the spread of malaria. Recently, a trial in Tanzania assessed the effectiveness of bed nets treated with a new insecticide, chlorfenapyr. The new insecticide is meant to tackle insecticide resistance associated with the widely used pyrethroid. The use of chlorfenapyr treated nets caused a significant reduction in malaria cases and 85% reduction in the number of malaria-infected mosquitoes. Thus, halving the cases of malaria infections in children in Tanzania.