Long-term impact of vaccine introduction on malaria cases and deaths in Sub-Saharan Africa: a modelling study
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Type
Journal Article
Abstract
Introduction Malaria is a potentially fatal, vector-borne disease, mainly impacting children under five. Although interventions have reduced its burden, recent progress has stalled, highlighting the need for new tools. Two new pre-erythrocytic vaccines R21/Matrix-M (R21) and RTS,S/AS01 began to be scaled up in 2024 and have the potential to greatly reduce malaria burden. Here, we use
mathematical modelling to estimate the potential long-term impact of vaccine rollout across Sub-Saharan Africa (SSA). Methods To estimate vaccine impact on malaria cases and deaths we utilised malariasimulation, an individual-based malaria transmission model that has previously been calibrated against phase II/III trial data for both vaccines. We estimated the impact of vaccine roll-out on malaria cases and deaths in all GAVI-supported moderate-to-high transmission first administrative level (admin-1) units in SSA using forecasts of vaccine coverage and type in children under 2 years old through to 2100 to capture lifetime vaccine impact. The model incorporates variation at the admin-1 level in parasite prevalence, seasonality, vector species, demography, and coverage of other non-vaccine malaria interventions. We assumed continuous stable coverage of non-vaccine malaria interventions. We implemented vaccination in a routine age-based fashion based on national immunisation schedules with forecasted coverage based on current coverage 17
of other vaccines. Results With a routine vaccination scenario introduced in 2023 and imperfect coverage, we estimate that vaccines will avert 591 million (95% uncertainty interval: 407 million-753 million) 20
malaria cases and 1.74 million (848,000-2.41 million) deaths in Africa through 2050. This represents 5.20% (4.79-5.74) of cases and 7.31% (5.24-9.28) of deaths between 2023 and 2050. From 2023 to 2100, the vaccine averted 3.81% (3.35-4.45) of malaria cases and 6.41% (3.58-9.40) of all malaria deaths in this region. The impact was greatest in children aged 5 or under (23.5%
[22.6-24.8] of malaria cases averted and 18.6% [16.3-21.0] of malaria deaths averted through 2100). We estimate the greatest vaccine impact in the initial years following vaccine introduction, with a decline as populations age and efficacy wanes at older ages.
Discussion Malaria vaccination could avert a substantial number of malaria cases and deaths across SSA in combination with existing interventions. Monitoring of longer-term vaccine effectiveness will be essential to support tailoring of strategies to prevent delayed malaria.
mathematical modelling to estimate the potential long-term impact of vaccine rollout across Sub-Saharan Africa (SSA). Methods To estimate vaccine impact on malaria cases and deaths we utilised malariasimulation, an individual-based malaria transmission model that has previously been calibrated against phase II/III trial data for both vaccines. We estimated the impact of vaccine roll-out on malaria cases and deaths in all GAVI-supported moderate-to-high transmission first administrative level (admin-1) units in SSA using forecasts of vaccine coverage and type in children under 2 years old through to 2100 to capture lifetime vaccine impact. The model incorporates variation at the admin-1 level in parasite prevalence, seasonality, vector species, demography, and coverage of other non-vaccine malaria interventions. We assumed continuous stable coverage of non-vaccine malaria interventions. We implemented vaccination in a routine age-based fashion based on national immunisation schedules with forecasted coverage based on current coverage 17
of other vaccines. Results With a routine vaccination scenario introduced in 2023 and imperfect coverage, we estimate that vaccines will avert 591 million (95% uncertainty interval: 407 million-753 million) 20
malaria cases and 1.74 million (848,000-2.41 million) deaths in Africa through 2050. This represents 5.20% (4.79-5.74) of cases and 7.31% (5.24-9.28) of deaths between 2023 and 2050. From 2023 to 2100, the vaccine averted 3.81% (3.35-4.45) of malaria cases and 6.41% (3.58-9.40) of all malaria deaths in this region. The impact was greatest in children aged 5 or under (23.5%
[22.6-24.8] of malaria cases averted and 18.6% [16.3-21.0] of malaria deaths averted through 2100). We estimate the greatest vaccine impact in the initial years following vaccine introduction, with a decline as populations age and efficacy wanes at older ages.
Discussion Malaria vaccination could avert a substantial number of malaria cases and deaths across SSA in combination with existing interventions. Monitoring of longer-term vaccine effectiveness will be essential to support tailoring of strategies to prevent delayed malaria.
Date Acceptance
2026-10-01
Citation
The Lancet Global Health
ISSN
2572-116X
Publisher
Elsevier
Journal / Book Title
The Lancet Global Health
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
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Accepted