Abstract
Vector control is a potentially effective intervention to augment annual mass drug administration (MDA) towards the elimination of lymphatic filariasis. We conducted cost-effectiveness analysis of MDA alone and augmented by VC using data from a cluster randomized trial and historical controls. We built on an effectiveness trial. It randomized 36 villages in the State of Tamil Nadu, India, at risk of LF transmission into three groups of 12 villages each: MDA alone (the standard of care); MDA plus expanded polystyrene beads (MDA+EPB) for covering the water surface in wells and cesspits to suppress the filariasis vector mosquito Culex quinquefasciatus; MDA plus integrated vector control combining EPB with insecticidal pyrethroid impregnated curtains (MDA+EPB+PIC) over windows, doors, and eaves. Economic costs in 2010 US$ combined village and higher levels. Outcomes were antigen prevalence (AGP), microfilaria prevalence
below the level for elimination (MFP<1%) from 2010 to 2013, and modeled Disability Adjusted Life Years (DALYs). The estimated annual cost per village resident was US$0.53 for MDA alone, US$1.02 for MDA+EPB, and US$1.83 for MDA+EPB+PIC. MDA and MDA+EPB+PIC increased the percentages of villages with MFP<1% by 67% and 75% of villages, respectively, although not statistically significant. The resulting incremental cost-effectiveness ratios per DALY averted were $7.2 and $141, respectively. The findings confirm that both MDA and MDA+EPB+PIC are both effective and very cost-effective strategies for eliminating LF. As MDA alone lowered MFP substantially and AGP takes years to change, the study had limited power to estimate the incremental benefits of vector control. While MDA+EPB+PIC costs three times as much as MDA alone, its substantially greater effectiveness makes it more cost-effective. This VC combination accelerates LF elimination by about one year and may contribute to LF elimination in defined communities