Malaria Vaccine Impact on Cases, Drug-resistant Cases, and Deaths in Africa: A Modeling Study

Abstract Background The emergence of antimalarial drug resistance poses a major threat to effective malaria treatment and control in sub-Saharan Africa. The RTS, S/AS01 vaccine has the potential to reduce both resistant infections and antimalarial use. Modeling studies projecting aggregate health burden averted under different scenarios can support further vaccine development and implementation. Methods A mathematical model projecting cases, drug-resistant cases, and deaths averted from 2021 to 2030 with a vaccine against clinical malaria caused by Plasmodium falciparum administered yearly to one-year-olds in the WHO Africa Region. Findings Under a scenario in which vaccine efficacy (VE) was constant at 40% for four years and dropped to 0% in year five, approximately 92.5 million cases, 700,000 resistant cases, and 253,000 deaths were averted by 2030. In a scenario in which VE began at 80% and dropped 20 percentage points each year, approximately 123 million cases, one million resistant cases, and 336,000 deaths were averted. The highest burden averted occurred when VE remained 40% for 10 years with approximately 151 million cases, 1.1 million resistant cases, and 411,000 deaths averted. In a scenario of rapidly increasing drug resistance and an effective vaccine, over 4.5 million resistant cases were averted. Interpretation Swift and widespread deployment of an effective malaria vaccine in Africa, alongside other prevention and control interventions, could substantially reduce health and economic burden caused by drug-resistant malaria. Funding This work was funded by a grant from the Bill & Melinda Gates Foundation (OPP1190803) to the Center for Disease Dynamics, Economics & Policy under the ARVac Consortium.