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 .
Distance to health services affects local-level vaccine efficacy for pneumococcal conjugate vaccine (PCV) among rural Filipino children
Significance Although pneumococcal conjugate vaccines ( PCVs ) are widely available in industrialized nations , the cost of these vaccines and the strategy of universal vaccination of infants , as endorsed by the World Health Organization , are daunting obstacles to the adoption of these vaccines in developing countries . Using spatial epidemiological methods to examine the spatial variation in vaccine efficacy ( VE ) in an 11-valent PCV trial in Bohol , Philippines , we suggest an alternative strategy to universal vaccination . Our main finding suggests that areas with poor access to healthcare have the highest VE . An alternative vaccination strategy could target vaccination to areas where children are most likely to benefit , rather than focus on nationwide immunization . Pneumococcal conjugate vaccines ( PCVs ) have demonstrated efficacy against childhood pneumococcal disease in several regions globally . We demonstrate how spatial epidemiological analysis of a PCV trial can assist in developing vaccination strategies that target specific geographic sub population s at greater risk for pneumococcal pneumonia . We conducted a secondary analysis of a r and omized , placebo-controlled , double-blind vaccine trial that examined the efficacy of an 11-valent PCV among children less than 2 y of age in Bohol , Philippines . Trial data were linked to the residential location of each participant using a geographic information system . We use spatial interpolation methods to create smoothed surface maps of vaccination rates and local-level vaccine efficacy across the study area . We then measure the relationship between distance to the main study hospital and local-level vaccine efficacy , controlling for ecological factors , using spatial autoregressive models with spatial autoregressive disturbances . We find a significant amount of spatial variation in vaccination rates across the study area . For the primary study endpoint vaccine efficacy increased with distance from the main study hospital from −14 % for children living less than 1.5 km from Bohol Regional Hospital ( BRH ) to 55 % for children living greater than 8.5 km from BRH . Spatial regression models indicated that after adjustment for ecological factors , distance to the main study hospital was positively related to vaccine efficacy , increasing at a rate of 4.5 % per kilometer distance . Because areas with poor access to care have significantly higher VE , targeted vaccination of children in these areas might allow for a more effective implementation of global programs
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 .