We identified three primary mechanisms of spillovers : reduced disease transmission , social proximity and substitution of re sources within households .
We found the strongest evidence for spillovers through reduced disease transmission , particularly vaccines and mass drug administration .
In general , the proportion of a population receiving an intervention was associated with improved health .
We found evidence of publication bias for certain spillover estimates but not for total or direct effects .
Conclusions We found the strongest evidence for spillovers from vaccines and mass drug administration to control infectious disease .
There was little high quality evidence of spillovers for other interventions
Background Many interventions delivered to improve health may benefit not only direct recipients but also people in close physical or social proximity .
Our objective was to review all published literature about the spillover effects of interventions on health outcomes in low-middle income countries and to identify methods used in estimating these effects .
The association between latrine use and trachoma: a secondary cohort analysis from a randomized clinical trial.
Latrine use has been promoted as a component of an integrated strategy for trachoma control . As part of a r and omized trial in Ethiopia , 12 communities received a mass azithromycin distribution followed by a latrine promotion intervention .  A r and om sample of children ages 0 - 9 years in each community was monitored longitudinally for ocular chlamydia . After latrine construction ended , those communities with a higher proportion of households using latrines were more likely to experience a reduction in the prevalence of ocular chlamydia . Specifically , for each 10 % increase in latrine use , there was a 2.0 % decrease ( 95 % confidence interval = 0.2 - 3.9 % decrease ) in the community prevalence of ocular chlamydia over the subsequent year ( P = 0.04 )
We identified three primary mechanisms of spillovers : reduced disease transmission , social proximity and substitution of re sources within households .
We found the strongest evidence for spillovers through reduced disease transmission , particularly vaccines and mass drug administration .
In general , the proportion of a population receiving an intervention was associated with improved health .
We found evidence of publication bias for certain spillover estimates but not for total or direct effects .
Conclusions We found the strongest evidence for spillovers from vaccines and mass drug administration to control infectious disease .
There was little high quality evidence of spillovers for other interventions
Background Many interventions delivered to improve health may benefit not only direct recipients but also people in close physical or social proximity .
Our objective was to review all published literature about the spillover effects of interventions on health outcomes in low-middle income countries and to identify methods used in estimating these effects .