Costing approaches for vaccine-preventable disease surveillance: Lessons from Ethiopia and Nepal

There is limited information about vaccine-preventable disease (VPD) surveillance cost. To address this gap, retrospective micro-costing studies of pre-COVID-19 pandemic VPD surveillance were conducted in Nepal and Ethiopia. Based on these evaluations-the sole cost evaluations on comprehensive VPD surveillance-this article provides methodological considerations and recommendations for other countries planning to conduct VPD surveillance costing studies to inform planning and budgeting.

The methods used for each study were systematically compared by key themes: costing perspective, cost categories, costing approach, allocation of shared costs, sampling criteria, extrapolation strategies, data collection, and analytic adjustments. For each theme, investigators identified methodologic challenges and potential strategies to address them, compared study methodologies to surveillance costing guidelines, and recommended practices for future such studies.

The studies used similar perspectives and VPD inclusion criteria. Costs in Nepal were collected and analyzed by a subset of surveillance core and support functions, whereas the Ethiopia study categorized costs using surveillance support functions from the Global Strategy on Comprehensive VPD Surveillance. A mix of random and purposive sampling of surveillance sites was used in both studies. Surveillance sites were selected considering the strata of interest at each administrative level. Results from both studies were extrapolated country-wide using sampling weights and assumptions about the representativeness of purposively sampled units.

The review highlighted potential methodologic tradeoffs in utility and precision of results based on the lessons learned from two country VPD surveillance cost studies. The advantages of collecting and using cost estimates by VPD surveillance core versus support function for program budgeting for varied audiences should be explored in future studies. Sampling strategies should be developed with consideration for the precision needed for the intended use of costing results. The resulting recommendations can improve and standardize the conduct and interpretation of future such studies.