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: Nosocomial influenza is a large burden in hospitals . Despite recommendations from the World Health Organization to vaccinate healthcare workers against influenza , vaccine uptake remains low in most European countries . We performed a pragmatic cluster r and omised controlled trial in order to assess the effects of implementing a multi-faceted influenza immunisation programme on vaccine coverage in hospital healthcare workers ( HCWs ) and on  in-patient morbidity . We included hospital HCWs of three intervention and three control University Medical Centers ( UMCs ) , and 3,367 patients . An implementation programme was offered to the intervention UMCs to assess the effects on both vaccine uptake among hospital staff and patient morbidity . In 2009/10 , the coverage of seasonal , the first and second dose of p and emic influenza vaccine  as well as seasonal vaccine in 2010/11 was higher in intervention UMCs than control UMCs ( all p<0.05 ) . At the internal medicine departments of the intervention group with higher vaccine coverage compared to the control group , nosocomial influenza and /or pneumonia was recorded in 3.9 % and 9.7 % of patients of intervention and control UMCs , respectively ( p=0.015 ) . Though potential bias could not be completely ruled out , an increase in vaccine coverage was associated with decreased patient in-hospital morbidity from influenza and /or pneumonia CONTEXT Data are limited and conflicting regarding the effectiveness of influenza vaccine in health care professionals . OBJECTIVE To determine the effectiveness of trivalent influenza vaccine in reducing infection , illness , and absence from work in young , healthy health care professionals . DESIGN R and omized , prospect i ve , double-blind , controlled trial over 3 consecutive years , from 1992 - 1993 to 1994 - 1995 . SETTING Two large teaching hospitals in Baltimore , Md. PARTICIPANTS Two hundred sixty-four hospital-based health care professionals without chronic medical problems were recruited ; 49 participated for 2 seasons ; 24 participated for 3 seasons . The mean age was 28.4 years , 75 % were resident physicians , and 57 % were women . INTERVENTION Participants were r and omly assigned to receive either an influenza vaccine or a control ( meningococcal vaccine , pneumococcal vaccine , or placebo ) . Serum sample s for antibody assays were collected at the time of vaccination , 1 month after vaccination , and at the end of the influenza season . Active weekly surveillance for illness was conducted during each influenza epidemic period . MAIN OUTCOME MEASURES Serologically defined influenza infection ( 4-fold increase in hemagglutination-inhibiting antibodies ) , days of febrile respiratory illness , and days absent from work . RESULTS We conducted 359 person-winters of serologic surveillance ( 99.4 % follow-up ) and 4746 person-weeks of illness surveillance ( 100 % follow-up ) . Twenty-four(13.4 % ) of 179 control subjects and 3 ( 1.7 % ) of 180 influenza vaccine recipients had serologic evidence of influenza type A or B infection during the study period . Vaccine efficacy against serologically defined infection was 88 % for influenza A ( 95 % confidence interval [ CI ] , 47%-97 % ; P=.001 ) and 89 % for influenza B ( 95 % CI , 14%-99 % ; P=.03 ) . Among influenza vaccinees , cumulative days of reported febrile respiratory illness were 28.7 per 100 subjects compared with 40.6 per 100 subjects in controls ( P=.57 ) and days of absence were 9.9 per 100 subjects vs 21.1 per 100 subjects in controls ( P=.41 ) . CONCLUSIONS Influenza vaccine is effective in preventing infection by influenza A and B in health care professionals and may reduce reported days of work absence and febrile respiratory illness . These data support a policy of annual influenza vaccination of health care professionals Background In acute-care hospitals , no evidence of a protective effect of healthcare worker ( HCW ) vaccination on hospital-acquired influenza ( HAI ) in patients has been documented . Our study objective was to ascertain the effectiveness of  influenza vaccination of HCW on HAI among patients . Methods A nested case-control investigation was implemented in a prospect i ve surveillance study of influenza-like illness ( ILI ) in a tertiary acute-care university hospital . Cases were patients with virologically-confirmed influenza occurring ≥ 72 h after admission , and controls were patients with ILI presenting during hospitalisation with negative influenza results after nasal swab testing . Four controls per case , matched per influenza season ( 2004 - 05 , 2005 - 06 and 2006 - 07 ) , were r and omly selected . Univariate and multivariate conditional logistic regression models were fitted to assess factors associated with HAI among patients . Results In total , among 55 patients analysed , 11 ( 20 % ) had laboratory-confirmed HAI . The median HCW vaccination rate in the units was 36 % . The median proportion of vaccinated HCW in these units was 11.5 % for cases vs. 36.1 % for the controls ( P = 0.11 ) ; 2 ( 20 % ) cases and 21 ( 48 % ) controls were vaccinated against influenza in the current season ( P = 0.16 ) . The proportion of ≥ 35 % vaccinated HCW in short-stay units appeared to protect against HAI among patients ( odds ratio = 0.07 ; 95 % confidence interval 0.005 - 0.98 ) , independently of patient age , influenza season and potential influenza source in the units . Conclusions Our observational study indicates a shielding effect of more than 35 % of vaccinated HCW on HAI among patients in acute-care units . Investigations , such as controlled clinical trials , are needed to vali date the benefits of HCW vaccination on HAI incidence in patients OBJECTIVES To evaluate the effect of staff influenza vaccination on all-cause mortality in nursing home residents . DESIGN Pair-matched cluster-r and omized trial . SETTING Forty nursing homes matched for size , staff vaccination coverage during the previous season , and resident disability index . PARTICIPANTS All persons aged 60 and older residing in the nursing homes . INTERVENTION Influenza vaccine was administered to volunteer staff after a face-to-face interview . No intervention took place in control nursing homes . MEASUREMENTS The primary endpoint was total mortality rate in residents from 2 weeks before to 2 weeks after the influenza epidemic in the community . Secondary endpoints were rates of hospitalization and influenza-like illness ( ILI ) in residents and sick leave from work in staff . RESULTS Staff influenza vaccination rates were 69.9 % in the vaccination arm versus 31.8 % in the control arm . Primary unadjusted analysis did not show significantly lower mortality in residents in the vaccination arm ( odds ratio=0.86 , P=.08 ) , although multivariate-adjusted analysis showed 20 % lower mortality ( P=.02 ) , and a strong correlation was observed between staff vaccination coverage and all-cause mortality in residents ( correlation coefficient=-0.42 , P=.007 ) . In the vaccination arm , significantly lower resident hospitalization rates were not observed , but ILI in residents was 31 % lower ( P=.007 ) , and sick leave from work in staff was 42 % lower ( P=.03 ) . CONCLUSION These results support influenza vaccination of staff caring for institutionalized elderly people Objective To determine whether vaccination of care home staff  against influenza indirectly protects residents . Design Pair matched cluster r and omised controlled trial . Setting Large private chain of UK care homes during the winters of 2003 - 4 and 2004 - 5 . Participants Nursing home staff ( n=1703 ) and residents ( n=2604 ) in 44 care homes ( 22 intervention homes and 22 matched control homes ) . Interventions Vaccination offered to staff in intervention homes but not in control homes . Main outcome measures The primary outcome was all cause mortality of residents . Secondary outcomes were influenza-like illness and health service use in residents . Results In 2003 - 4 vaccine coverage in full time staff was 48.2 % ( 407/884 ) in intervention homes and 5.9 % ( 51/859 ) in control homes . In 2004 - 5 uptake rates were 43.2 % ( 365/844 ) and 3.5 % ( 28/800 ) . National influenza rates were substantially below average in 2004 - 5 . In the 2003 - 4 period of influenza activity significant decreases were found in mortality of residents in intervention homes compared with control homes ( rate difference −5.0 per 100 residents , 95 % confidence interval −7.0 to −2.0 ) and in influenza-like illness ( P=0.004 ) , consultations with general practitioners for influenza-like illness ( P=0.008 ) , and admissions to hospital with influenza-like illness ( P=0.009 ) . No significant differences were found in 2004 - 5 or during periods of no influenza activity in 2003 - 4 . Conclusions Vaccinating care home staff against influenza can prevent deaths , health service use , and influenza-like illness in residents during periods of moderate influenza activity . Trial registration National Research Register N0530147256 Clinical illness case definitions for influenza and methods used to define influenza seasons can vary substantially from study to study . These differences often result in differing levels of sensitivity , specificity and positive predictive value for the case definitions used . We explored the implication s of different case definitions and outcome periods on estimates of influenza vaccine  effectiveness and cost benefit by conducting additional analyses of data collected from a r and omized , double blind , placebo controlled trial of the trivalent , intranasal , live attenuated influenza virus vaccine in healthy working adults . Febrile upper respiratory tract illnesses occurring during the peak influenza period was identified as the most specific clinical case definition expected to have the highest positive predictive value for true influenza whereas events occurring on a day with any symptom occurring during the entire outcome period was identified as the most sensitive clinical case definition with the lowest positive predictive value for influenza . As expected , the former provided the highest estimates of vaccine effectiveness ( 28.4 % reduction in work loss days , 24.6 % reduction in days with impaired productivity and 40.9 % reduction in days with health care provider visits ) but the lowest estimates of absolute reductions in events ( 42.4 work loss days prevented per 1000 , 79.0 impaired productivity days per 1000 , and 16.5 days with health care provider visits per 1000 ) . On the other h and , events on days with any symptom during the entire outcome period provided the lowest estimates of vaccine effectiveness ( 18 % reduction in work loss days , 18 % reduction in days with impaired productivity , and 13 % reduction in days with health care provider visits ) but the highest estimates of absolute reductions in events ( 186.4 work loss days per 1000 , 271.5 impaired productivity days per 1000 , and 44.8 days with health care provider visits per 1000 ) . When applied to a cost benefit analysis , the more specific case definition provided a break even cost for vaccination of US$ 6.58 whereas the more sensitive case definition provided a break even cost for vaccination of US$ 43.07 . Clearly the latter combination is most appropriate when trying to assess the total population level impact of a vaccine preventable disease and the potential cost effectiveness of vaccination whereas the former may be most appropriate for assessing whether the vaccine actually works . The definitions of clinical influenza illness and outcome periods should be selected to match the study question BACKGROUND Vaccination of health-care workers has been cl aim ed to prevent nosocomial influenza infection of elderly patients in long-term care . Data are , however , limited on this strategy . We aim ed to find out whether vaccination of health-care workers lowers mortality and the frequency of virologically proven influenza in such patients . METHODS In a parallel-group study , health-care workers in 20 long-term elderly-care hospitals ( range 44 - 105 patients ) were r and omly offered  or not offered influenza vaccine  ( cluster r and omisation , stratified for policy for vaccination of patients and hospital size ) . All deaths among patients were recorded over 6 months in the winter of 1996 - 97 . We selected a r and om sample of 50 % of patients for virological surveillance for influenza , with combined nasal and throat swabs taken every 2 weeks during the epidemic period . Swabs were tested by tissue culture and PCR for influenza viruses A and B. FINDINGS Influenza vaccine uptake in health-care workers was 50.9 % in hospitals in which they were routinely offered vaccine , compared with 4.9 % in those in which they were not . The uncorrected rate of mortality in patients was 102 ( 13.6 % ) of 749 in vaccine hospitals compared with 154 ( 22.4 % ) of 688 in no-vaccine hospitals ( odds ratio 
    Output:
    
agent
***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: Nosocomial influenza is a large burden in hospitals . Despite recommendations from the World Health Organization to vaccinate healthcare workers against influenza , vaccine uptake remains low in most European countries . We performed a pragmatic cluster r and omised controlled trial in order to assess the effects of implementing a multi-faceted influenza immunisation programme on vaccine coverage in hospital healthcare workers ( HCWs ) and on  in-patient morbidity . We included hospital HCWs of three intervention and three control University Medical Centers ( UMCs ) , and 3,367 patients . An implementation programme was offered to the intervention UMCs to assess the effects on both vaccine uptake among hospital staff and patient morbidity . In 2009/10 , the coverage of seasonal , the first and second dose of p and emic influenza vaccine  as well as seasonal vaccine in 2010/11 was higher in intervention UMCs than control UMCs ( all p<0.05 ) . At the internal medicine departments of the intervention group with higher vaccine coverage compared to the control group , nosocomial influenza and /or pneumonia was recorded in 3.9 % and 9.7 % of patients of intervention and control UMCs , respectively ( p=0.015 ) . Though potential bias could not be completely ruled out , an increase in vaccine coverage was associated with decreased patient in-hospital morbidity from influenza and /or pneumonia CONTEXT Data are limited and conflicting regarding the effectiveness of influenza vaccine in health care professionals . OBJECTIVE To determine the effectiveness of trivalent influenza vaccine in reducing infection , illness , and absence from work in young , healthy health care professionals . DESIGN R and omized , prospect i ve , double-blind , controlled trial over 3 consecutive years , from 1992 - 1993 to 1994 - 1995 . SETTING Two large teaching hospitals in Baltimore , Md. PARTICIPANTS Two hundred sixty-four hospital-based health care professionals without chronic medical problems were recruited ; 49 participated for 2 seasons ; 24 participated for 3 seasons . The mean age was 28.4 years , 75 % were resident physicians , and 57 % were women . INTERVENTION Participants were r and omly assigned to receive either an influenza vaccine or a control ( meningococcal vaccine , pneumococcal vaccine , or placebo ) . Serum sample s for antibody assays were collected at the time of vaccination , 1 month after vaccination , and at the end of the influenza season . Active weekly surveillance for illness was conducted during each influenza epidemic period . MAIN OUTCOME MEASURES Serologically defined influenza infection ( 4-fold increase in hemagglutination-inhibiting antibodies ) , days of febrile respiratory illness , and days absent from work . RESULTS We conducted 359 person-winters of serologic surveillance ( 99.4 % follow-up ) and 4746 person-weeks of illness surveillance ( 100 % follow-up ) . Twenty-four(13.4 % ) of 179 control subjects and 3 ( 1.7 % ) of 180 influenza vaccine recipients had serologic evidence of influenza type A or B infection during the study period . Vaccine efficacy against serologically defined infection was 88 % for influenza A ( 95 % confidence interval [ CI ] , 47%-97 % ; P=.001 ) and 89 % for influenza B ( 95 % CI , 14%-99 % ; P=.03 ) . Among influenza vaccinees , cumulative days of reported febrile respiratory illness were 28.7 per 100 subjects compared with 40.6 per 100 subjects in controls ( P=.57 ) and days of absence were 9.9 per 100 subjects vs 21.1 per 100 subjects in controls ( P=.41 ) . CONCLUSIONS Influenza vaccine is effective in preventing infection by influenza A and B in health care professionals and may reduce reported days of work absence and febrile respiratory illness . These data support a policy of annual influenza vaccination of health care professionals Background In acute-care hospitals , no evidence of a protective effect of healthcare worker ( HCW ) vaccination on hospital-acquired influenza ( HAI ) in patients has been documented . Our study objective was to ascertain the effectiveness of  influenza vaccination of HCW on HAI among patients . Methods A nested case-control investigation was implemented in a prospect i ve surveillance study of influenza-like illness ( ILI ) in a tertiary acute-care university hospital . Cases were patients with virologically-confirmed influenza occurring ≥ 72 h after admission , and controls were patients with ILI presenting during hospitalisation with negative influenza results after nasal swab testing . Four controls per case , matched per influenza season ( 2004 - 05 , 2005 - 06 and 2006 - 07 ) , were r and omly selected . Univariate and multivariate conditional logistic regression models were fitted to assess factors associated with HAI among patients . Results In total , among 55 patients analysed , 11 ( 20 % ) had laboratory-confirmed HAI . The median HCW vaccination rate in the units was 36 % . The median proportion of vaccinated HCW in these units was 11.5 % for cases vs. 36.1 % for the controls ( P = 0.11 ) ; 2 ( 20 % ) cases and 21 ( 48 % ) controls were vaccinated against influenza in the current season ( P = 0.16 ) . The proportion of ≥ 35 % vaccinated HCW in short-stay units appeared to protect against HAI among patients ( odds ratio = 0.07 ; 95 % confidence interval 0.005 - 0.98 ) , independently of patient age , influenza season and potential influenza source in the units . Conclusions Our observational study indicates a shielding effect of more than 35 % of vaccinated HCW on HAI among patients in acute-care units . Investigations , such as controlled clinical trials , are needed to vali date the benefits of HCW vaccination on HAI incidence in patients OBJECTIVES To evaluate the effect of staff influenza vaccination on all-cause mortality in nursing home residents . DESIGN Pair-matched cluster-r and omized trial . SETTING Forty nursing homes matched for size , staff vaccination coverage during the previous season , and resident disability index . PARTICIPANTS All persons aged 60 and older residing in the nursing homes . INTERVENTION Influenza vaccine was administered to volunteer staff after a face-to-face interview . No intervention took place in control nursing homes . MEASUREMENTS The primary endpoint was total mortality rate in residents from 2 weeks before to 2 weeks after the influenza epidemic in the community . Secondary endpoints were rates of hospitalization and influenza-like illness ( ILI ) in residents and sick leave from work in staff . RESULTS Staff influenza vaccination rates were 69.9 % in the vaccination arm versus 31.8 % in the control arm . Primary unadjusted analysis did not show significantly lower mortality in residents in the vaccination arm ( odds ratio=0.86 , P=.08 ) , although multivariate-adjusted analysis showed 20 % lower mortality ( P=.02 ) , and a strong correlation was observed between staff vaccination coverage and all-cause mortality in residents ( correlation coefficient=-0.42 , P=.007 ) . In the vaccination arm , significantly lower resident hospitalization rates were not observed , but ILI in residents was 31 % lower ( P=.007 ) , and sick leave from work in staff was 42 % lower ( P=.03 ) . CONCLUSION These results support influenza vaccination of staff caring for institutionalized elderly people Objective To determine whether vaccination of care home staff  against influenza indirectly protects residents . Design Pair matched cluster r and omised controlled trial . Setting Large private chain of UK care homes during the winters of 2003 - 4 and 2004 - 5 . Participants Nursing home staff ( n=1703 ) and residents ( n=2604 ) in 44 care homes ( 22 intervention homes and 22 matched control homes ) . Interventions Vaccination offered to staff in intervention homes but not in control homes . Main outcome measures The primary outcome was all cause mortality of residents . Secondary outcomes were influenza-like illness and health service use in residents . Results In 2003 - 4 vaccine coverage in full time staff was 48.2 % ( 407/884 ) in intervention homes and 5.9 % ( 51/859 ) in control homes . In 2004 - 5 uptake rates were 43.2 % ( 365/844 ) and 3.5 % ( 28/800 ) . National influenza rates were substantially below average in 2004 - 5 . In the 2003 - 4 period of influenza activity significant decreases were found in mortality of residents in intervention homes compared with control homes ( rate difference −5.0 per 100 residents , 95 % confidence interval −7.0 to −2.0 ) and in influenza-like illness ( P=0.004 ) , consultations with general practitioners for influenza-like illness ( P=0.008 ) , and admissions to hospital with influenza-like illness ( P=0.009 ) . No significant differences were found in 2004 - 5 or during periods of no influenza activity in 2003 - 4 . Conclusions Vaccinating care home staff against influenza can prevent deaths , health service use , and influenza-like illness in residents during periods of moderate influenza activity . Trial registration National Research Register N0530147256 Clinical illness case definitions for influenza and methods used to define influenza seasons can vary substantially from study to study . These differences often result in differing levels of sensitivity , specificity and positive predictive value for the case definitions used . We explored the implication s of different case definitions and outcome periods on estimates of influenza vaccine  effectiveness and cost benefit by conducting additional analyses of data collected from a r and omized , double blind , placebo controlled trial of the trivalent , intranasal , live attenuated influenza virus vaccine in healthy working adults . Febrile upper respiratory tract illnesses occurring during the peak influenza period was identified as the most specific clinical case definition expected to have the highest positive predictive value for true influenza whereas events occurring on a day with any symptom occurring during the entire outcome period was identified as the most sensitive clinical case definition with the lowest positive predictive value for influenza . As expected , the former provided the highest estimates of vaccine effectiveness ( 28.4 % reduction in work loss days , 24.6 % reduction in days with impaired productivity and 40.9 % reduction in days with health care provider visits ) but the lowest estimates of absolute reductions in events ( 42.4 work loss days prevented per 1000 , 79.0 impaired productivity days per 1000 , and 16.5 days with health care provider visits per 1000 ) . On the other h and , events on days with any symptom during the entire outcome period provided the lowest estimates of vaccine effectiveness ( 18 % reduction in work loss days , 18 % reduction in days with impaired productivity , and 13 % reduction in days with health care provider visits ) but the highest estimates of absolute reductions in events ( 186.4 work loss days per 1000 , 271.5 impaired productivity days per 1000 , and 44.8 days with health care provider visits per 1000 ) . When applied to a cost benefit analysis , the more specific case definition provided a break even cost for vaccination of US$ 6.58 whereas the more sensitive case definition provided a break even cost for vaccination of US$ 43.07 . Clearly the latter combination is most appropriate when trying to assess the total population level impact of a vaccine preventable disease and the potential cost effectiveness of vaccination whereas the former may be most appropriate for assessing whether the vaccine actually works . The definitions of clinical influenza illness and outcome periods should be selected to match the study question BACKGROUND Vaccination of health-care workers has been cl aim ed to prevent nosocomial influenza infection of elderly patients in long-term care . Data are , however , limited on this strategy . We aim ed to find out whether vaccination of health-care workers lowers mortality and the frequency of virologically proven influenza in such patients . METHODS In a parallel-group study , health-care workers in 20 long-term elderly-care hospitals ( range 44 - 105 patients ) were r and omly offered  or not offered influenza vaccine  ( cluster r and omisation , stratified for policy for vaccination of patients and hospital size ) . All deaths among patients were recorded over 6 months in the winter of 1996 - 97 . We selected a r and om sample of 50 % of patients for virological surveillance for influenza , with combined nasal and throat swabs taken every 2 weeks during the epidemic period . Swabs were tested by tissue culture and PCR for influenza viruses A and B. FINDINGS Influenza vaccine uptake in health-care workers was 50.9 % in hospitals in which they were routinely offered vaccine , compared with 4.9 % in those in which they were not . The uncorrected rate of mortality in patients was 102 ( 13.6 % ) of 749 in vaccine hospitals compared with 154 ( 22.4 % ) of 688 in no-vaccine hospitals ( odds ratio 
    Output:
    