Landmark Lancet Study Confirms RTS,S Malaria Vaccine Averts One in Eight Child Deaths Across Pilot Nations

Geneva, Switzerland – May 8, 2026

A rigorous four-year evaluation of the RTS,S/AS01E malaria vaccine, published today in The Lancet, has confirmed that the world's first malaria vaccine prevented roughly one in eight child deaths across the three African nations that pioneered its rollout.

The study, which tracked the Malaria Vaccine Implementation Programme (MVIP) from 2019 to 2023 in Ghana, Kenya, and Malawi, found a 13.2% reduction in all-cause mortality among eligible children — a figure the authors describe as achievable even at moderate vaccine coverage levels.

Study Design and Scale

The evaluation was unprecedented in its scope. Researchers randomly assigned 158 administrative clusters — each with a birth cohort of roughly 4,000 children — across the three pilot countries. Seventy-nine areas introduced the vaccine in 2019, while 79 comparison areas received it later.

Surveillance was built on a network of more than 26,000 local community reporters who notified researchers of child deaths in their areas, followed by home visits from study staff to confirm details through verbal autopsy. Eighteen sentinel hospitals conducted strengthened surveillance for severe malaria over 46 months.

"This is very solid evidence of the potential for malaria vaccines to change the trajectory of child mortality in Africa, and why it is urgent to overcome funding challenges to accelerate rollout."

— Dr Kate O'Brien, WHO Director of the Department of Immunization, Vaccines and Biologicals, and co-author of the evaluation

Key Findings

The results, published in The Lancet on May 8, 2026, establish several critical evidence points:

Mortality Impact

Over the four-year evaluation period, 5,576 deaths occurred in implementation areas compared with 6,152 in comparison areas among children eligible for the third vaccine dose. The mortality rate ratio was 0.87 — translating to a 13.2% reduction in all-cause child mortality.

The mortality benefit held equally for girls and boys, with no significant difference by sex or country. This consistency across different transmission dynamics and parasite populations suggests that vaccine effectiveness does not vary significantly by setting.

Severe Malaria Reduction

Hospital admissions for severe malaria fell by 22%, confirming earlier data from the first two years of the programme that had informed WHO's 2021 recommendation. Critically, the evaluation found no evidence of the safety signals — excess meningitis, cerebral malaria, or deaths in girls — that had been flagged in the original Phase 3 trial.

Coverage and Dose Completion

By 2022, uptake was 82.8% for the first dose, 71.1% for the third dose, and 39.9% for the fourth dose. By the end of the evaluation, nearly 1.3 million children had received the first dose, 1.1 million the second, 1.07 million the third, and 436,527 the fourth.

The finding that substantial mortality reductions were achieved at moderate coverage eases earlier concerns that the vaccine's public health value depended on high four-dose completion rates.

No Crowding Out of Other Interventions

A significant concern during the pilot was whether adding a malaria vaccine to childhood immunisation schedules would displace other health interventions. The evaluation found the opposite.

Uptake of routine childhood vaccines and use of insecticide-treated bed-nets remained steady throughout the evaluation. A meaningful share of children who were not sleeping under bed-nets still received the malaria vaccine, broadening the overall proportion of children with access to at least one form of malaria prevention.

The four-dose schedule also created additional touchpoints with the health system. The study authors note that these visits could be used to simultaneously deliver other childhood vaccines such as measles or meningitis vaccine, as well as vitamin A supplementation or bed-nets.

Implications for Wider Rollout

The findings carry direct implications for the 25 sub-Saharan African countries that have now added malaria vaccines to their childhood immunisation programmes. More than 10 million children each year are targeted for malaria vaccination across these nations.

According to WHO, many of these countries have malaria burdens at least as high as — or higher than — the pilot areas. Positive impact is likely to be as great or greater if similar coverage levels can be achieved.

Antimalarial Drug Resistance

In a related commentary in The Lancet, Claudia Daubenberger of the University of Basel and Ally Olotu of the Ifakara Health Institute in Tanzania noted that vaccines such as RTS,S can lower the emergence and spread of antimalarial drug resistance by reducing disease incidence and thereby reducing the use of antimalarial drugs.

"This will reduce the selection pressure favouring resistant parasites, thereby limiting their transmission and slowing the spread of resistance over time. By reducing febrile illness, RTS,S may, in addition, reduce empirical antibiotic use in settings with limited diagnostic capacity, lowering emergence and spread of antimicrobial resistance."

— Claudia Daubenberger, University of Basel, and Ally Olotu, Ifakara Health Institute

However, they cautioned that the study was limited by low uptake of the fourth dose across all implementation clusters, noting that it remains unclear how much greater the mortality reduction might be with higher coverage.

Funding Gap Remains

Despite sufficient vaccine supply to meet current demand, funding constraints are preventing many countries from scaling up malaria vaccination to national targets and sustaining coverage already achieved.

Dr O'Brien emphasised that demand is high and supply is sufficient, but more financing is needed so countries can purchase enough vaccine — along with other malaria prevention tools — to reach all children most at risk of serious disease or death.

"In many areas where malaria vaccines are most urgently needed, vaccine delivery is often constrained by weak health systems, mistrust, and conflict."

— Study authors, The Lancet, May 2026

Research Collaboration

The evaluation involved scientists and public health specialists from WHO, Africa-based research institutions, and international partners. Primary MVIP evaluation partners included the Kintampo Health Research Centre in Ghana, the Kenya Medical Research Institute-Wellcome Trust in Kenya, Kamuzu University of Health Sciences in Malawi, the London School of Hygiene and Tropical Medicine, and the U.S. Centers for Disease Control and Prevention.

Two WHO-recommended malaria vaccines — RTS,S/AS01 and R21/Matrix-M — are now available for the prevention of Plasmodium falciparum malaria in children, prioritised for areas of moderate to high transmission.

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Source: The Lancet, May 8, 2026. WHO News Release, May 8, 2026. CIDRAP News, May 12, 2026. GAVI VaccinesWork, May 12, 2026.