Comparison of an integrated versus stand-alone approach to post-validation surveillance for lymphatic filariasis in Niue: a micro-costing study, 2025

Background: Lymphatic filariasis (LF) is a mosquito-borne parasitic disease caused by three species of filarial worm: Wuchereria bancrofti, Brugia malayi and B. timori. The early stages of infection are often asymptomatic; yet, chronic infection may result in lymphoedema, elephantiasis, and hydrocele, imposing significant social and economic burdens. Global initiatives have dramatically reduced prevalence and transmission, and Niue, a self-governing South Pacific Island country with approximately 1,600 residents, was validated by the World Health Organization (WHO) in 2016 as having eliminated LF as a public-health problem. To ensure that transmission does not re-emerge after elimination, the WHO recommends post-validation surveillance (PVS). An integrated surveillance approach, whereby LF surveillance activities are incorporated into existing health survey programs, may reduce costs and improve operational feasibility. This approach is recommended by WHO. This study employs a micro-costing framework to compare the costs of a recently implemented integrated LF-PVS approach in Niue with the counterfactual of a stand-alone LF-PVS.Methods: Costs were estimated from the perspective of the implementing agency and the national health authority. Using a bottom-up micro-costing approach, activities and resources were itemised and unit costs assigned. Data were drawn from project budgets, accounting records and staff reports. For the stand-alone scenario, all LF survey activities (community engagement, consent, blood collection, specimen testing, data analysis, travel, and the dissemination of results) were assumed to be conducted by three implementing agency staff, with only essential involvement of Department of Health (DOH) personnel. For the integrated scenario, LF-PVS activities were embedded within the 2025 national WHO STEPwise survey for non-communicable disease risk factors, with two external research staff and one DOH officer responsible for blood collection and field laboratory activities. Assumptions across both scenarios included a five-week survey period (25 survey days) and factor in the frequency of travel to/from Niue. All costs are reported in United States dollars (US$) 2025 prices.Results: The integrated approach required fewer personnel and leveraged existing STEPwise arrangements, resources, and processes, saving personnel time and cost. Overall, the stand-alone approach cost about 1.7 times than the integrated approach. Total provider costs under the integrated scenario were US$59,488 compared with US$105,414 for the stand-alone survey. The integrated cost per participant tested was US$59, compared to US$105 for the stand-alone approach, representing a 44% reduction. Staffing was the largest cost driver, accounting for ~47% of the difference. Pre-survey community engagement, sampling and data collection, and dissemination activities were conducted jointly with STEPwise activities in the integrated scenario, resulting in savings. DOH staff time required decreased from 38.1 person-days for the stand-alone scenario to 20.1 person-days for the integrated scenario, resulting in savings of 18 days, or ~4 weeks of a full-time equivalent staff member.Conclusions: Embedding LF PVS within the national STEPwise survey in Niue substantially reduced the financial and human resource requirements compared with a stand-alone survey. This analysis provides evidence that programmatic integration of LF-PVS serosurveillance both reduces overall cost