human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Vaccination of one person may prevent the infection of another either because the vaccine prevents the first from being infected and from infecting the second , or because , even if the first person is infected , the vaccine may render the infection less infectious . We might refer to the first of these mechanisms as a contagion effect and the second as an infectiousness effect . In the simple setting of a r and omized vaccine trial with households of size two , we use counterfactual theory under interference to provide formal definitions of a contagion effect and an unconditional infectiousness effect . Using ideas analogous to mediation analysis , we show that the indirect effect ( the effect of one person 's vaccine on another 's outcome ) can be decomposed into a contagion effect and an unconditional infectiousness effect on the risk difference , risk ratio , odds ratio , and vaccine efficacy scales . We provide identification assumptions for such contagion and unconditional infectiousness effects and describe a simple statistical technique to estimate these effects when they are identified . We also give a sensitivity analysis technique to assess how inferences would change under violations of the identification assumptions . The concepts and results of this paper are illustrated with hypothetical vaccine trial data BACKGROUND We evaluated the herd protection conferred by an oral cholera vaccine using 2 approaches : cluster design and geographic information system ( GIS ) design . METHODS Residents living in 3933 dwellings ( clusters ) in Kolkata , India , were cluster-r and omized to receive either cholera vaccine or oral placebo . Nonpregnant residents aged≥1 year were invited to participate in the trial . Only the first episode of cholera detected for a subject between 14 and 1095 days after a second dose was considered . In the cluster design , indirect protection was assessed by comparing the incidence of cholera among non participants in vaccine clusters vs those in placebo clusters . In the GIS analysis , herd protection was assessed by evaluating association between vaccine coverage among the population residing within 250 m of the household and the occurrence of cholera in that population . RESULTS Among 107 347 eligible residents , 66 990 received 2 doses of either cholera vaccine or placebo . In the cluster design , the 3-year data showed significant total protection ( 66 % protection , 95 % confidence interval [ CI ] , 50%-78 % , P<.01 ) but no evidence of indirect protection . With the GIS approach , the risk of cholera among placebo recipients was inversely related to neighborhood-level vaccine coverage , and the trend was highly significant ( P<.01 ) . This relationship held in multivariable models that also controlled for potentially confounding demographic variables ( hazard ratio , 0.94 [ 95 % CI , .90-.98 ] ; P<.01 ) . CONCLUSIONS Indirect protection was evident in analyses using the GIS approach but not the cluster design approach , likely owing to considerable transmission of cholera between clusters , which would vitiate herd protection in the cluster analyses . CLINICAL TRIALS REGISTRATION NCT00289224 Spatial analyses of the effect of insecticide (permethrin)-treated bed nets ( ITNs ) on nearby households both with and without ITNs was performed in the context of a large-scale , group-r and omized , controlled mortality trial in Asembo , western Kenya . Results illustrate a protective effect of ITNs on compounds lacking ITNs located within 300 meters of compounds with ITNs for child mortality , moderate anemia , high-density parasitemia , and hemoglobin levels . This community effect on nearby compounds without nets is approximately as strong as the effect observed within villages with ITNs . This implies that in areas with intense malaria transmission with high ITN coverage , the primary effect of insecticide-treated nets is via area-wide effects on the mosquito population and not , as commonly supposed , by simple imposition of a physical barrier protecting individuals from biting . The strength of the community effect depended upon the proportion of nearby compounds with treated nets . To maximize their public health impact , high coverage with treated nets is essential Objective To assess the efficacy of modest non-financial incentives on immunisation rates in children aged 1 - 3 and to compare it with the effect of only improving the reliability of the supply of services . Design Clustered r and omised controlled study . Setting Rural Rajasthan , India . Participants 1640 children aged 1 - 3 at end point . Interventions 134 villages were r and omised to one of three groups : a once monthly reliable immunisation camp  ( intervention A ; 379 children from 30 villages ) ; a once monthly reliable immunisation camp with small incentives ( raw lentils and metal plates for completed immunisation ;  intervention B ; 382 children from 30 villages ) , or  control ( no intervention , 860 children in 74 villages ) . Surveys were undertaken in r and omly selected households at baseline and about 18 months after the interventions started ( end point ) . Main outcome measures Proportion of children aged 1 - 3 at the end point who were partially or fully immunised . Results Among children aged 1 - 3 in the end point survey , rates of full immunisation were 39 % ( 148/382 , 95 % confidence interval 30 % to 47 % ) for intervention B villages ( reliable immunisation with incentives ) , 18 % ( 68/379 , 11 % to 23 % ) for intervention A villages ( reliable immunisation without incentives ) , and 6 % ( 50/860 , 3 % to 9 % ) for control villages . The relative risk of complete immunisation for intervention B versus control was 6.7 ( 4.5 to 8.8 ) and for intervention B versus intervention A was 2.2 ( 1.5 to 2.8 ) . Children in areas neighbouring intervention B villages were also more likely to be fully immunised than those from areas neighbouring intervention A villages ( 1.9 , 1.1 to 2.8 ) . The average cost per immunisation was $ 28 ( 1102 rupees , about £ 16 or € 19 ) in intervention A and $ 56 ( 2202 rupees ) in intervention B. Conclusions Improving reliability of services improves immunisation rates , but the effect remains modest . Small incentives have large positive impacts on the uptake of immunisation services in re source poor areas and are more cost effective than purely improving supply . Trial registration IRSCTN87759937 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 Invasive pneumococcal disease in adults may be declining , reflecting a form of herd protection from a new pediatric pneumococcal conjugate vaccine . Our aim was to determine whether vaccination of children protects adults in the same home from bacteremic pneumococcal pneumonia . We conducted a case-control study with 43 participating hospitals across a five-county region in Pennsylvania . Eligible cases were adults with bacteremic pneumococcal pneumonia identified by the microbiology laboratories at participating hospitals . Controls were healthy adults from the region identified through r and om digit dialing . Cases and controls were interviewed by telephone . We analyzed vaccine protection in those adults who reported living in homes with at least one child < or = 6 years of age . From April 2002 through June 2004 , there was a significant decline in the proportion of adult pneumococcal bacteremia due to any of the seven serotypes in the conjugate vaccine ( p=0.006 ) . Within this time period , 17 % of cases and controls reported living in homes with at least one child < or = 6 years of age . In adjusted analysis , vaccination of the youngest child in the home was associated with an 80 % reduction in the odds of bacteremic pneumococcal pneumonia among adults with children in the home ( OR=0.2 , 95 % CI 0.1 - 0.8 ) . We conclude that introduction of a pneumococcal conjugate vaccine for children has reduced the population rate of adult pneumococcal bacteremia due to vaccine serotypes and is associated with a reduced risk of bacteremic pneumococcal pneumonia for adults with children in the home OBJECTIVES The effectiveness of vaccines in population s must consider both direct and indirect protection . This study reanalyses data from a large individually r and omized oral cholera vaccine trial that was conducted in rural Bangladesh from 1985 to 1990 . A recent analysis of the results of that trial showed that the proportion of people in household clusters who received the vaccine was inversely related to placebo incidence during the first year of surveillance , which was attributed to herd immunity . METHODS In this study we measure the relationship between  neighbourhood-level oral cholera vaccine coverage and protective efficacy ( PE ) during a 2 year follow-up period , controlling for known effect modifiers . We link trial data to a household geographic information system to facilitate the neighbourhood-level analysis . Findings Neighbourhood-level PE can be partially explained by vaccine coverage after adjusting for ecological variables . CONCLUSIONS The inverse relationship between vaccine coverage and efficacy illustrates that people living in high-coverage areas may be indirectly protected from cholera because people living around them are vaccinated 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 ) OBJECTIVES We evaluated the effectiveness and spillover of an after-school health education and physical activity program among Hispanic elementary school children . METHODS In fall 2008 , students in third through fifth grade s in 6 schools in El Paso , Texas ( n = 901 ) , were r and omized to intervention ( n = 292 participants ) or control ( n = 354 ) classrooms ( 4 unknown ) . Intervention classrooms also contained a spillover group ( n = 251 ) that did not join the after-school program but that completed measurements and surveys . The intervention was a 12-week culturally tailored after-school program meeting twice a week . Four-month outcomes were body mass index , aerobic capacity , and dietary intentions and knowledge . We calculated intervention exposure as the proportion of after-school participants per classroom . RESULTS Intervention exposure predicted lower body mass index ( P = .045 ) , higher aerobic capacity ( P = .012 ) , and greater intentions to eat healthy ( P = .046 ) for the classroom at follow-up . Intervention effectiveness increased with increasing proportions of inter 
    Output:
    
agent
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
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Vaccination of one person may prevent the infection of another either because the vaccine prevents the first from being infected and from infecting the second , or because , even if the first person is infected , the vaccine may render the infection less infectious . We might refer to the first of these mechanisms as a contagion effect and the second as an infectiousness effect . In the simple setting of a r and omized vaccine trial with households of size two , we use counterfactual theory under interference to provide formal definitions of a contagion effect and an unconditional infectiousness effect . Using ideas analogous to mediation analysis , we show that the indirect effect ( the effect of one person 's vaccine on another 's outcome ) can be decomposed into a contagion effect and an unconditional infectiousness effect on the risk difference , risk ratio , odds ratio , and vaccine efficacy scales . We provide identification assumptions for such contagion and unconditional infectiousness effects and describe a simple statistical technique to estimate these effects when they are identified . We also give a sensitivity analysis technique to assess how inferences would change under violations of the identification assumptions . The concepts and results of this paper are illustrated with hypothetical vaccine trial data BACKGROUND We evaluated the herd protection conferred by an oral cholera vaccine using 2 approaches : cluster design and geographic information system ( GIS ) design . METHODS Residents living in 3933 dwellings ( clusters ) in Kolkata , India , were cluster-r and omized to receive either cholera vaccine or oral placebo . Nonpregnant residents aged≥1 year were invited to participate in the trial . Only the first episode of cholera detected for a subject between 14 and 1095 days after a second dose was considered . In the cluster design , indirect protection was assessed by comparing the incidence of cholera among non participants in vaccine clusters vs those in placebo clusters . In the GIS analysis , herd protection was assessed by evaluating association between vaccine coverage among the population residing within 250 m of the household and the occurrence of cholera in that population . RESULTS Among 107 347 eligible residents , 66 990 received 2 doses of either cholera vaccine or placebo . In the cluster design , the 3-year data showed significant total protection ( 66 % protection , 95 % confidence interval [ CI ] , 50%-78 % , P<.01 ) but no evidence of indirect protection . With the GIS approach , the risk of cholera among placebo recipients was inversely related to neighborhood-level vaccine coverage , and the trend was highly significant ( P<.01 ) . This relationship held in multivariable models that also controlled for potentially confounding demographic variables ( hazard ratio , 0.94 [ 95 % CI , .90-.98 ] ; P<.01 ) . CONCLUSIONS Indirect protection was evident in analyses using the GIS approach but not the cluster design approach , likely owing to considerable transmission of cholera between clusters , which would vitiate herd protection in the cluster analyses . CLINICAL TRIALS REGISTRATION NCT00289224 Spatial analyses of the effect of insecticide (permethrin)-treated bed nets ( ITNs ) on nearby households both with and without ITNs was performed in the context of a large-scale , group-r and omized , controlled mortality trial in Asembo , western Kenya . Results illustrate a protective effect of ITNs on compounds lacking ITNs located within 300 meters of compounds with ITNs for child mortality , moderate anemia , high-density parasitemia , and hemoglobin levels . This community effect on nearby compounds without nets is approximately as strong as the effect observed within villages with ITNs . This implies that in areas with intense malaria transmission with high ITN coverage , the primary effect of insecticide-treated nets is via area-wide effects on the mosquito population and not , as commonly supposed , by simple imposition of a physical barrier protecting individuals from biting . The strength of the community effect depended upon the proportion of nearby compounds with treated nets . To maximize their public health impact , high coverage with treated nets is essential Objective To assess the efficacy of modest non-financial incentives on immunisation rates in children aged 1 - 3 and to compare it with the effect of only improving the reliability of the supply of services . Design Clustered r and omised controlled study . Setting Rural Rajasthan , India . Participants 1640 children aged 1 - 3 at end point . Interventions 134 villages were r and omised to one of three groups : a once monthly reliable immunisation camp  ( intervention A ; 379 children from 30 villages ) ; a once monthly reliable immunisation camp with small incentives ( raw lentils and metal plates for completed immunisation ;  intervention B ; 382 children from 30 villages ) , or  control ( no intervention , 860 children in 74 villages ) . Surveys were undertaken in r and omly selected households at baseline and about 18 months after the interventions started ( end point ) . Main outcome measures Proportion of children aged 1 - 3 at the end point who were partially or fully immunised . Results Among children aged 1 - 3 in the end point survey , rates of full immunisation were 39 % ( 148/382 , 95 % confidence interval 30 % to 47 % ) for intervention B villages ( reliable immunisation with incentives ) , 18 % ( 68/379 , 11 % to 23 % ) for intervention A villages ( reliable immunisation without incentives ) , and 6 % ( 50/860 , 3 % to 9 % ) for control villages . The relative risk of complete immunisation for intervention B versus control was 6.7 ( 4.5 to 8.8 ) and for intervention B versus intervention A was 2.2 ( 1.5 to 2.8 ) . Children in areas neighbouring intervention B villages were also more likely to be fully immunised than those from areas neighbouring intervention A villages ( 1.9 , 1.1 to 2.8 ) . The average cost per immunisation was $ 28 ( 1102 rupees , about £ 16 or € 19 ) in intervention A and $ 56 ( 2202 rupees ) in intervention B. Conclusions Improving reliability of services improves immunisation rates , but the effect remains modest . Small incentives have large positive impacts on the uptake of immunisation services in re source poor areas and are more cost effective than purely improving supply . Trial registration IRSCTN87759937 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 Invasive pneumococcal disease in adults may be declining , reflecting a form of herd protection from a new pediatric pneumococcal conjugate vaccine . Our aim was to determine whether vaccination of children protects adults in the same home from bacteremic pneumococcal pneumonia . We conducted a case-control study with 43 participating hospitals across a five-county region in Pennsylvania . Eligible cases were adults with bacteremic pneumococcal pneumonia identified by the microbiology laboratories at participating hospitals . Controls were healthy adults from the region identified through r and om digit dialing . Cases and controls were interviewed by telephone . We analyzed vaccine protection in those adults who reported living in homes with at least one child < or = 6 years of age . From April 2002 through June 2004 , there was a significant decline in the proportion of adult pneumococcal bacteremia due to any of the seven serotypes in the conjugate vaccine ( p=0.006 ) . Within this time period , 17 % of cases and controls reported living in homes with at least one child < or = 6 years of age . In adjusted analysis , vaccination of the youngest child in the home was associated with an 80 % reduction in the odds of bacteremic pneumococcal pneumonia among adults with children in the home ( OR=0.2 , 95 % CI 0.1 - 0.8 ) . We conclude that introduction of a pneumococcal conjugate vaccine for children has reduced the population rate of adult pneumococcal bacteremia due to vaccine serotypes and is associated with a reduced risk of bacteremic pneumococcal pneumonia for adults with children in the home OBJECTIVES The effectiveness of vaccines in population s must consider both direct and indirect protection . This study reanalyses data from a large individually r and omized oral cholera vaccine trial that was conducted in rural Bangladesh from 1985 to 1990 . A recent analysis of the results of that trial showed that the proportion of people in household clusters who received the vaccine was inversely related to placebo incidence during the first year of surveillance , which was attributed to herd immunity . METHODS In this study we measure the relationship between  neighbourhood-level oral cholera vaccine coverage and protective efficacy ( PE ) during a 2 year follow-up period , controlling for known effect modifiers . We link trial data to a household geographic information system to facilitate the neighbourhood-level analysis . Findings Neighbourhood-level PE can be partially explained by vaccine coverage after adjusting for ecological variables . CONCLUSIONS The inverse relationship between vaccine coverage and efficacy illustrates that people living in high-coverage areas may be indirectly protected from cholera because people living around them are vaccinated 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 ) OBJECTIVES We evaluated the effectiveness and spillover of an after-school health education and physical activity program among Hispanic elementary school children . METHODS In fall 2008 , students in third through fifth grade s in 6 schools in El Paso , Texas ( n = 901 ) , were r and omized to intervention ( n = 292 participants ) or control ( n = 354 ) classrooms ( 4 unknown ) . Intervention classrooms also contained a spillover group ( n = 251 ) that did not join the after-school program but that completed measurements and surveys . The intervention was a 12-week culturally tailored after-school program meeting twice a week . Four-month outcomes were body mass index , aerobic capacity , and dietary intentions and knowledge . We calculated intervention exposure as the proportion of after-school participants per classroom . RESULTS Intervention exposure predicted lower body mass index ( P = .045 ) , higher aerobic capacity ( P = .012 ) , and greater intentions to eat healthy ( P = .046 ) for the classroom at follow-up . Intervention effectiveness increased with increasing proportions of inter 
    Output:
    