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 .
Effect of scaling up women's groups on birth outcomes in three rural districts in Bangladesh: a cluster-randomised controlled trial
BACKGROUND Two recent trials have shown that women 's groups can reduce neonatal mortality in poor communities . We assessed the effectiveness of a scaled-up development programme with women 's groups to address maternal and neonatal care in three rural districts of Bangladesh . METHODS 18 clusters ( with a mean population of 27 953 [ SD 5953 ] ) in three districts were r and omly assigned to either intervention or control ( nine clusters each ) by use of stratified r and omisation . For each district , cluster names were written on pieces of paper , which were folded and placed in a bottle . The first three cluster names drawn from the bottle were allocated to the intervention group and the remaining three to control . All clusters received health services strengthening and basic training of traditional birth attendants . In intervention clusters , a facilitator convened 18 groups every month to support participatory action and learning for women , and to develop and implement strategies to address maternal and neonatal health problems . Women were eligible to participate if they were aged 15 - 49 years , residing in the project area , and had given birth during the study period ( Feb 1 , 2005 , to Dec 31 , 2007 ) . Neither study investigators nor participants were masked to treatment assignment . In a population of 229 195 people ( intervention clusters only ) , 162 women 's groups provided coverage of one group per 1414 population . The primary outcome was neonatal mortality rate ( NMR ) . Analysis was by intention to treat . This trial is registered as an International St and ard R and omised Controlled Trial , number IS RCT N54792066 . FINDINGS We monitored outcomes for 36 113 births ( intervention clusters , n=17 514 ; control clusters , n=18 599 ) in a population of 503 163 over 3 years . From 2005 to 2007 , there were 570 neonatal deaths in the intervention clusters and 656 in the control clusters . Cluster-level mean NMR ( adjusted for stratification and clustering ) was 33.9 deaths per 1000 livebirths in the intervention clusters compared with 36.5 per 1000 in the control clusters ( risk ratio 0.93 , 95 % CI 0.80 - 1.09 ) . INTERPRETATION For participatory women 's groups to have a significant effect on neonatal mortality in rural Bangladesh , detailed attention to programme design and context ual factors , enhanced population coverage , and increased enrolment of newly pregnant women might be needed . FUNDING Women and Children First , the UK Big Lottery Fund , Saving Newborn Lives , and the UK Department for International Development
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 .