Advancing malaria vaccines: A new era in global health
Recent advancements in malaria vaccines offer hope for reducing cases in endemic communities
Key Takeaways
- Recent advancements in malaria vaccines, notably the R21 vaccine, show promising results, with 70-80% efficacy in reducing cases among young children in endemic areas.
- Implementation challenges, such as the need for four doses and the vaccine’s short shelf life, require careful logistical planning and community education.
Malaria claims more than half a million lives annually around the world, with children under 5 years old bearing the brunt of its impact. Despite decades of efforts to control the mosquito-borne disease, it has proven difficult to develop a vaccine that can fight the complex parasite before it rapidly multiplies in the liver and attacks red blood cells. But recent advancements offer hope.
A new short film “The Battle to Beat Malaria,” recently screened at the Johns Hopkins University Bloomberg Center, follows scientists on their journey to develop the R21 vaccine, showcasing their triumphs and tragedies along the way.
Vaccine development and successes
In 1951, the U.S. was declared malaria-free. Yet even today people in Sub-Saharan Africa continue to face a high number of malaria cases. The first malaria-fighting vaccine, RTS,S, was produced in the late 1990s and implemented in 2019, but improvements in manufacturing and effectiveness were still needed.
In 2012, the second malaria vaccine, R21, was created, and by 2023, the World Health Organization gave its stamp of approval. Since its creation, R21 has undergone extensive trials, particularly in young children. With efficacy rates around 70-80%, it has been proven to reduce cases of malaria.
While developing these vaccines, researchers debated which stage of the parasite’s life cycle is the best target for the vaccine to attack. Like its predecessor, R21 is designed to attack the sporozoite stage, which is the form of the parasite that first enters the human body. This stage is less likely to mutate, making it a good target for vaccination.
Room for improvements
However, the years of malaria research are still far from over and advancements can still be made. After a screening of the film,David Walton, U.S. global malaria coordinator at the President’s Malaria Initiative, warned that implementing the vaccine can pose challenges similar to the developmental stage.
“What you saw is the herculean task of the upstream work to develop the science and to develop the vaccine,” Walton said. “And now comes the second herculean task, to actually implement.”
To maximize R21’s effectiveness, children must receive three doses when they are between five and nine months old, and another dose in their second year of life. But the requirement of four doses presents logistical issues, especially in regions with limited access to health care. There is also concern about the short shelf life of R21. The vaccine expires after 18 months, which can complicate storage and distribution, particularly in those remote areas.
What’s next?
The future of malaria prevention appears promising, but it will require ongoing commitment to finding ways to gain higher efficacy, longer-lasting immunity, and improved scheduling of boosters. Ashley Birkett, the global head of bacterial and parasitic diseases at the Center for Vaccine Innovation and Access, said past trials have equipped researchers with valuable insights.
“The large Phase 3 studies that we’ve had, first for the RTS,S vaccine, and then R21, have taught us so much about how to run these studies going forward,” Birkett said. “So I think we’re very well equipped, in terms of the capabilities in the countries, to run these trials and the types of things that we need to look out for that we probably hadn’t considered when we got into this.”
Global collaboration remains vital, and organizations like PMI and local governments must work together to ensure adequate funding, infrastructure, and education. Simon Mutembo, an assistant scientist at the International Vaccine Access Center, said as the vaccines roll out, it is important that the affected communities view them as additive to other safety precautions, such as bed nets, and not as a replacement.
At the end of October, the Democratic Republic of Congo became the 15th nation in Africa to roll out R21 vaccines; 16 more are expected to implement it by the end of 2024.