The economic value of increasing geospatial access to tetanus toxoid immunization in Mozambique

Abstract

Background: With tetanus being a leading cause of maternal and neonatal morbidity and mortality in low and middle income countries, ensuring that pregnant women have geographic access to tetanus toxoid (TT) immunization can be important. However, immunization locations in many systems may not be placed to optimize access across the population. Issues of access must be addressed for vaccines such as TT to reach their full potential.

Methods: To assess how TT immunization locations meet population demand in Mozambique, our team developed and utilized SIGMA (Strategic Integrated Geo-temporal Mapping Application) to quantify how many pregnant women are reachable by existing TT immunization locations, how many cannot access these locations, and the potential costs and disease burden of not covering geographically harder-to-reach populations. Sensitivity analyses covered a range of catchment area sizes to include realistic travel distances and to determine the area some locations would need to cover in order for the existing system to reach at least 99% of the target population.

Results: For 99% of the population to reach health centers, people would be required to travel up to 35km. Limiting this distance to 15km would result in 5450 (3033-7108) annual cases of neonatal tetanus that could be prevented by TT, 144,240 (79,878-192,866) DALYs, and $110,691,979 ($56,180,326-$159,516,629) in treatment costs and productivity losses. A catchment area radius of 5km would lead to 17,841 (9929-23,271) annual cases of neonatal tetanus that could be prevented by TT, resulting in 472,234 (261,517-631,432) DALYs and $362,399,320 ($183,931,229-$522,248,480) in treatment costs and productivity losses.

Conclusion: TT immunization locations are not geographically accessible by a significant proportion of pregnant women, resulting in substantial healthcare and productivity costs that could potentially be averted by adding or reconfiguring TT immunization locations. The resulting cost savings of covering these harder to reach populations could help pay for establishing additional immunization locations.

Keywords: Access; Geospatial analysis; Immunization; Tetanus.

Figure 1. Percentage of TT target population covered versus catchment area size in Mozambique

Figure 2. SIGMA visualizations of TT immunization locations and their catchment areas

Each health center and its catchment is plotted as a blue circle onto a population density map of Mozambique, in which higher intensity red indicates greater density of the TT target population. Any population not covered by a blue circle is considered to be unreachable by immunization locations. Six example scenarios from sensitivity analyses are shown, with catchment area radii of (A) 3km, (B) 5km, (C) 7km, (D) 15km, (E) 20km, and (F) 35km.