ESTIMATING THE IMPACT OF PNEUMOCOCCAL CONJUGATE VACCINES IN RESOURCE-POOR SETTINGS: A PORTABLE HEALTH POLICY MODEL FOR NEW VACCINE INTRODUCTION

Purpose: Despite its potential to significantly reduce under-five disease burden, the high price of pneumococcal conjugate vaccine (PCV) has deterred introduction in many countries. We have developed an interactive, portable health policy analysis software tool capable of modeling the outcomes of different vaccine introduction programs based on country level data that can support vaccine decision making in resource-constrained settings.

Method: A comprehensive on-line decision analytic model was developed to estimate the direct effects of PCV, while the results of a dynamic transmission model were adapted to estimate the indirect effects (herd protection and serotype replacement). The structure of the model allows for ten sequential cross-sectional under-five child populations to be followed, with health outcomes aggregated by year for 10 years.  Both of the available vaccine products (PCV-10 and PCV-13), all WHO-approved vaccination schedules, and catch-up campaigns are modeled, as well as a “no vaccination” scenario. Data sets were constructed for each country, using estimates from recent global analyses of disease burden and epidemiology, life table data, and other internationally available data sources, including unit costs from World Health Organization's CHOICE project and vaccine-related costs from comprehensive multi-year planning data. The model is embedded in a general purpose decision support framework consisting of a series of dynamic web pages that provide complete documentation of all model parameters and allows policy makers to enter new values. The use of standard HTML pages makes the decision support framework platform-independent and operable on any computer with a web browser, while the interface and evaluable model can also be accessed in areas without internet access via CD-ROM.  

Result: The model has been fully populated with data to evaluate the cost-effectiveness of PCV for 23 low-income countries. Policy-makers and analysts can choose their own web-browser to access the model and modify the baseline model inputs to conduct sensitivity analyses and obtain results from both the healthcare and societal perspectives.

Conclusion: This decision support tool is an efficient, low-cost method for geographically dispersed analysts, with no special training in decision analysis, to enter specific data for their countries or regions of choice into a web-browser, and adapt the tool to project and compare disease burden and cost outcomes for their unique locations and vaccination strategies of interests.