Cost-effectiveness of vector control strategies for supplementing mass drug administration for eliminating lymphatic filariasis in India

Abstract

AbstractBackground/MethodologyDespite progress using mass drug administration (MDA), lymphatic filariasis (LF) remains a major public health issue in India. Vector control (VC) is hypothesized as a potentially useful addition to MDA towards LF elimination. We conducted cost-effectiveness analysis of MDA alone and augmented by VC single (VCS) or integrated VC approaches (VCI). Data came from historical controls and a 3-arm cluster randomized trial of 36 villages at risk of LF transmission in Tamil Nadu, India. The arms were: MDA alone (the standard of care); VCS (MDA plus expanded polystyrene beads for covering the water surface in wells and cesspits to suppress the filariasis vector mosquitoCulex quinquefasciatus), and VCI (VCS plus insecticidal pyrethroid impregnated curtains over windows, doors, and eaves). Economic costs in 2010 US$ combined government and community inputs from household to state levels. Outcomes were controlled microfilaria prevalence (MfP) and antigen prevalence (AgP) to conventional elimination targets (MfP<1% and AgP<2%) from 2010 to 2013, and disability adjusted life years (DALYs) averted.Principal FindingsThe estimated annual economic cost per resident was US$0.53 for MDA alone, US$1.02 for VCS, and US$1.83 for VCI. With MDA offered in all arms, all reduced LF prevalence substantially and significantly from 2010 to 2013. MDA proved highly cost effective at $112 per DALY, a very small (8%) share of India’s then per capita GDP. Progress towards elimination was comparable across all three study arms.ConclusionsThe well-functioning MDA was effective and very cost-effective for eliminating LF, leaving little scope for further improvement. Supplementary VC demonstrated no statistically significant additional benefit in this trial.Authors’ SummaryLymphatic filariasis (LF) is one of the twenty neglected tropical diseases (NTDs) that affect more than one billion people worldwide. As part of the effort toward global elimination of LF, the Indian State of Tamil Nadu government has implemented mass drug administration (MDA) repeatedly since 1996. Despite their efforts, LF had not yet been eliminated. Although vector control (VC) is proposed to augment regular MDA to help eliminate LF, little is known about the increased impact or costs. Our study compares the costs of MDA alone to the combination of MDA with alternative VC interventions. We calculated both program operating costs and costs to communities. We found MDA to be very cost-effective for eliminating LF. Against low levels of LF endemicity (≤10%), the study had limited ability to detect further improvements and found no significant incremental improvements from VC.