Table 1.

Definitions of PHS in SCORE field studies

SCORE study	Definition of PHS
Sustaining and gaining control studies	Villages that failed to achieve at least a 35% decrease in prevalence relative to baseline and/or a 50% decrease in infection intensity relative to baseline after 4 years of mass drug administration, either annually or twice in 4 years
Kenya and Tanzania factors study	Villages with a starting prevalence of ≥ 50% that remained at ≥ 25% prevalence at the end of the study while responders reduced to a < 25% prevalence, or those with a starting prevalence of 25–49% that remained at ≥ 10% prevalence at the end of the study while responders reduced to < 10% prevalence
Zanzibar elimination study	Shehias with a prevalence ≥ 10% at baseline and ≥ 5% at the end of the study

PHS = persistent hotspots; SCORE = Schistosomiasis Consortium for Operational Research and Evaluation.