A vaccine unlike most others
Malaria has an unusual place in the history of vaccines.
Vaccines train the immune system to recognize a biological threat, but malaria is caused by a parasite rather than a virus or bacterium. Developing an effective vaccine proved extraordinarily difficult.
RTS,S eventually became the first malaria vaccine recommended by the World Health Organization in 2021, followed by a second vaccine, R21, in 2023.
But recommending a vaccine and proving that it changes lives at population scale are different things.
Beginning in 2019, Ghana, Kenya and Malawi introduced RTS,S through ordinary childhood immunization programs in selected areas. More than two million children eventually participated in the Malaria Vaccine Implementation Programme.
The program also created an unusual opportunity to measure what happened next.
From efficacy to lives saved
The four-year evaluation published in The Lancet in May 2026 compared 158 geographic clusters: 79 introduced the vaccine and 79 initially did not.
Researchers tracked deaths among vaccine-age-eligible children and monitored other factors that could distort the comparison.
The result was a 13% reduction in all-cause mortality excluding injury associated with introducing the vaccine.
Hospitalizations for severe malaria declined by 22%.
Using all-cause mortality deserves explanation.
Determining whether malaria caused a child's death can be surprisingly difficult, particularly when a child dies at home without a medical diagnosis. Even in hospitals, malaria infection may be the primary cause, a contributing factor or incidental.
Researchers therefore used deaths from all causes other than injury as their primary mortality measure.
That makes the result broader than counting diagnosed malaria deaths—and potentially more reliable for determining whether introducing the vaccine actually kept children alive.
It worked without perfect coverage
There is another encouraging aspect of the result.
The vaccination program wasn't perfect.
About 71% of eligible children received three doses, while only about 40% received the fourth during the evaluation.
Yet the population-level mortality benefit remained substantial.
That's particularly relevant because the places that stand to benefit most from malaria vaccination can also have health systems facing shortages, conflict, mistrust and difficulty getting families back for repeated appointments.
The implementation problems remain important, but the study shows meaningful reductions in mortality are possible even with moderate coverage.
From three countries to 25
The story has already moved beyond the original pilot.
As of February 2026, WHO reported that 25 African countries were offering malaria vaccines, targeting more than 10 million children annually.
Two vaccines—RTS,S and R21—are now WHO-recommended.
And the scale of the opportunity is enormous.
Malaria caused an estimated 610,000 deaths worldwide in 2024. About 438,000 of those deaths were African children.
WHO estimates that scaling malaria vaccination across moderate- and high-transmission areas could prevent approximately half a million child deaths by 2035.
That figure is a projection, not an accomplished result.
What comes next
The scientific breakthrough is increasingly becoming an implementation challenge.
Countries need money to purchase vaccines and maintain vaccination programs. Children need to receive multiple doses. Bed nets, treatment and other malaria interventions need to continue alongside vaccination.
But something fundamental has changed.
For much of modern medical history, a malaria vaccine was an objective researchers were trying to reach.
Today there are two WHO-recommended vaccines, millions of children have received them, and a large real-world evaluation has found that introducing vaccination reduced childhood mortality.
The promise has become measurable progress.