Abstract
Background
Recent recommendation of the RTS,S vaccine has equipped the global public health community with a valuable tool for malaria prevention. We conduct a return-on-investment (ROI) analysis of the introduction and continuation of the four-dose RTS,S vaccine in the routine immunization systems of 49 Gavi-supported countries in sub-Saharan Africa from 2021-2030.
Methods
The ROI model consists of two sub-models, which calculate the economic benefits and programmatic costs of routine RTS,S introduction and continuation within Gavi-supported countries in sub-Saharan Africa. Benefits are estimated using a cost-of-illness (COI) approach with malaria case and death data provided by Swiss Tropical and Public Health Institute (STPH) and Imperial College London (ICL). Costs are calculated from Gavi vaccine and vaccination material prices, Gavi dose demand forecasting data, and delivery costs per dose estimated by PATH and the Johns Hopkins University Decade of Vaccine Economics (DoVE) project. Cost-of-illness averted is assessed following the methodology laid out in computing the ROI for other Gavi-supported vaccines conducted under the DoVE project. Four vaccine dose cost scenarios are considered: a base case of 7 USD per dose, a minimum price of 2 USD per dose, a median price of 5 USD per dose, and a maximum price of 10 USD per dose. Additionally, we consider the inclusion of a fifth seasonal RTS,S dose delivered via supplementary immunization activities for the 10 sub-Saharan African countries that experience high seasonal malaria transmission.
Results
Using STPH impact estimates, RTS,S programs can avert 4.04 billion (3.92–4.18 billion) USD in COI under the STPH scenario whereas that of the ICL scenario is 9.41 billion (9.14–9.69) USD. Among uncomplicated malaria costs, 84.5% (STPH) and 83.7% (ICL) are owed to productivity loss due to disability. For severe malaria, 90.8% (STPH) and 83.7% (ICL) of costs are attributed to productivity loss due to death.
The base case vaccine price using STPH impact data yields an ROI of 0.42 (0.28–0.53) for 2021-2030. Under the minimum price scenario, the ROI increases to 2.36 (1.76–3.05) while the ROI decreases to 0.05 (-0.03–0.12) for a maximum vaccine price of 10 USD. The base case ROI from the ICL impact model is estimated to be 2.30 (2.00–2.57) for 2021-2030. For, the minimum vaccine price of 2 USD, the ROI increases to 6.83 (5.39 – 8.46) while the ROI decreases to 1.45 (1.28–1.60) for a maximum vaccine price of 10 USD. When incorporating the seasonal 5th dose, the base case ROI increases by 142.9% to 1.02 (0.85–1.18) for the STPH model and by 24.5% to 2.84 (2.50–3.14) for the ICL model.
Conclusion
Our results suggest that integration of RTS,S vaccines into the immunization systems of sub-Saharan African Gavi-supported countries yield substantial ROIs, assuming mid- and low- vaccination price per dose estimates. Despite higher costs, ROIs are higher when including a seasonal 5th dose in high seasonal transmission settings when compared to a 4-dose schedule. Estimates from this study can inform policymakers to develop effective strategies for resource mobilization to ensure sustainable immunization programs.