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: 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 Although current guidelines target hospital employees who contact high-risk patients as a high priority for influenza immunization , there are few data to support or refute this recommendation . Therefore , the authors enrolled 179 hospital employees in a r and omized double-blind  placebo-controlled  clinical trial during the 1985–1986 influenza season .  Influenza immunization was performed without serious adverse reactions and there was no increase in absenteeism attributable to the vaccination . Among those who developed clinical influenza , there was a trend toward fewer days of illness in the vaccinated group compared with the placebo group ( 6.0 vs. 8.0 , p=0.07 ) . There were no statistically significant differences between subjects receiving influenza vaccine and those receiving the placebo when comparing incidences of influenza-like illness , severities of illness , and sick absenteeism .  Influenza immunization of hospital employees was performed at minimal cost and risk but provided little benefit , most likely because of an unexpected drift of the prevalent influenza strain away from the vaccine type BACKGROUND Successful treatment of influenza depends on an accurate diagnosis of the illness and prompt intervention . However , there is a lack of data comparing clinical diagnosis vs laboratory diagnostic techniques . OBJECTIVE To compare the clinical diagnosis of community cases of influenza with various laboratory diagnostic techniques including multiplex , reverse transcription polymerase chain reaction . METHODS Clinical diagnosis , viral isolation , hemagglutinin inhibition serology , and multiplex , reverse transcription polymerase chain reaction were used to diagnose influenza in patients enrolled in international phase 3 studies design ed to investigate the efficacy and safety of an anti-influenza drug ( inhaled zanamivir ) .  Patients clinical ly diagnosed with influenza were enrolled at centers across North America and Europe . RESULTS A total of 791 ( 77 % ) of 1033 patients with laboratory results from all 3 methods were confirmed positive for influenza by 1 or more test results . For 692 patients ( 67 % ) , the results of all 3 tests agreed . Total symptom scores at baseline showed a significant association toward greater severity of symptoms with an increasing number of positive test results ( P<.001 ) . An increasing number of positive test results also showed a significant correlation with a longer time to alleviation of symptoms of influenza in the placebo group ( P = .001 ) . CONCLUSIONS During a time when influenza was known to be circulating and clinical diagnostic criteria were applied , diagnosis of influenza in these trials was accurate in approximately 77 % of adults on clinical grounds alone . This highlights the need for primary care physicians to be alerted to circulating influenza and to be aware that presentation with cough and fever provide the most predictive symptoms BACKGROUND In healthy adults  influenza immunization reduces absenteeism caused by respiratory infections , but data on its efficacy among health care workers are scarce . OBJECTIVE To determine the effect of the conventional inactivated influenza A vaccine on reducing absenteeism related to respiratory infections among pediatric health care providers . STUDY DESIGN A r and omized , placebo-controlled , double blind study on vaccine efficacy was conducted in two pediatric hospitals during the winter season 1996 to 1997 . The primary endpoint was days of work lost from the hospital because of respiratory infections . The documentation of absenteeism was based on personal sickness logs . RESULTS Of the 547 r and omized vaccinees 427 ( 78 % ) persons completed the 4-month follow-up and returned the sickness logs . Immunization failed to reduce episodes of respiratory infections ( 1.8 episodes/ study period among vaccinees vs. 2.0 among controls ) . Similarly the vaccine failed to affect the total number of days the vaccinees suffered from respiratory infections ( 13.5 days vs. 14.6 days , respectively ) . However , days of work lost because of respiratory infections ( 1.0 days vs. 1.4 days , respectively , P = 0.02 ) and especially total numbers of days the study persons felt themselves unable to work when either on or off duty ( 2.5 days vs. 3.5 days , P 0.02 ) were significantly decreased . CONCLUSION Influenza vaccination reduced absenteeism related to respiratory infections by 28 % . We therefore believe that routine annual influenza immunizations should be recommended to health care providers working in pediatric setting INTRODUCTION Influenza vaccine has been shown to be highly effective in temperate regions with well-defined seasonal influenza . Healthcare workers ( HCWs ) are advised to receive regular influenza vaccination to protect themselves and their patients . However , there are limited data on the efficacy of influenza vaccine in HCWs in the tropics . MATERIAL S AND METHODS In this observational , investigator blinded cohort study , bi-monthly question naires recording influenza-like illness ( ILI ) episodes and medical leave were administered to 541 HCWs at the Singapore National University Hospital and KK Women 's and Children 's Hospital from 2004 to 2005 .  ILI was defined according to a st and ard symptom score . RESULTS Baseline characteristics were comparable in both the vaccinated and non-vaccinated groups . Overall , the relative risk of self-reported ILI in vaccinated HCWs was 1.13 [ 95 % confidence interval ( CI ) , 0.98 - 1.13 ; P=0.107 ] ; medical leave taken was lower in the vaccinated group [ mean 0.26+/-0.6 days per visit , compared with 0.30+/-0.5 days in the non-vaccinated group ( P=0.40 ) ] . Because of the reported Northern Hemisphere 2003/04 vaccine mismatch , we stratified the cohort and determined that the group which received a matched vaccine had a relative risk of ILI of 0.49 ( 95 % CI , 0.37 - 0.66 ; P<0.001 ) , achieving a vaccine efficacy of 51 % . Mean medical leave decreased significantly in HCWs who received the matched vaccine , compared with those who did not receive vaccination ( 0.13+/-0.3 vs 0.30+/-0.5 ; P<0.001 ) and with HCWs vaccinated with mismatched strains ( 0.13+/-0.3 vs 0.39+/-0.9 ; P=0.01 ) . CONCLUSIONS A well-matched influenza vaccine is effective in preventing ILI and reducing sickness absence in healthcare workers in tropical setting s. Efforts need to be made to increase influenza vaccination rates and to improve the currently available vaccines Background Four cluster r and omized controlled trials ( c RCTs ) conducted in long-term care facilities ( LTCFs ) have reported reductions in patient risk through increased healthcare worker ( HCW ) influenza vaccination . This evidence has led to expansive policies of enforcement that include all staff of acute care hospitals and other healthcare setting s beyond LTCFs . We critique and quantify the c RCT evidence for indirect patient benefit underpinning policies of m and atory HCW influenza vaccination . Methods Plausibility of the four c RCT findings attributing indirect patient benefits to HCW influenza vaccination was assessed by comparing percentage reductions in patient risk reported by the c RCTs to predicted values . Plausibly predicted values were derived according to the basic mathematical principle of dilution , taking into account HCW influenza vaccine coverage and the specificity of patient outcomes for influenza . Accordingly , predicted values were calculated as a function of relevant compound probabilities including vaccine efficacy ( ranging 40–60 % in HCWs and favourably assuming the same indirect protection conferred through them to patients ) × change in proportionate HCW influenza vaccine coverage ( as reported by each c RCT ) × percentage of a given patient outcome ( e.g. influenza-like illness ( ILI ) or all-cause mortality ) plausibly due to influenza virus . The number needed to vaccinate ( NNV ) for HCWs to indirectly prevent patient death was recalibrated based on real patient data of hospital-acquired influenza , with adjustment for potential under-detection ( 5.2-fold ) , and using favourable assumptions of HCW-attributable risk ( ranging 60–80 % ) . Results In attributing patient benefit to increased HCW influenza vaccine coverage , each c RCT was found to violate the basic mathematical principle of dilution by reporting greater percentage reductions with less influenza-specific patient outcomes ( i.e. , all-cause mortality > ILI > laboratory-confirmed influenza ) and /or patient mortality reductions exceeding even favourably-derived predicted values by at least 6- to 15-fold . If extrapolated to all LTCF and hospital staff in the United States , the prior c RCT -cl aim ed NNV of 8 would implausibly mean > 200,000 and > 675,000 patient deaths , respectively , could be prevented annually by HCW influenza vaccination , inconceivably exceeding total US population mortality estimates due to seasonal influenza each year , or during the 1918 p and emic , respectively . More realistic recalibration based on actual patient data instead shows that at least 6000 to 32,000 hospital workers would need to be vaccinated before a single patient death could potentially be averted . Conclusions The four c RCTs underpinning policies of enforced HCW influenza vaccination attribute implausibly large reductions in patient risk to HCW vaccination , casting serious doubts on their validity . The impression that unvaccinated HCWs place their patients at great influenza peril is exaggerated . Instead , the HCW-attributable risk and vaccine-preventable fraction both remain unknown and the NNV to achieve patient benefit still requires better underst and ing . Although current scientific data are inadequate to support the ethical implementation of enforced HCW influenza vaccination , they do not refute approaches to support voluntary vaccination or other more broadly protective practice s , such as staying home or masking when acutely ill BACKGROUND Recently , lower estimates of influenza vaccine effectiveness ( VE ) against A(H3N2 ) virus illness among those vaccinated during the previous season or multiple seasons have been reported ; however , it is unclear whether these effects are due to differences in immunogenicity . METHODS We performed hemagglutination inhibition antibody ( HI ) assays on serum collected at preseason , ∼ 30 days post-vaccination , and postseason from a prospect i ve cohort of healthcare personnel ( HCP ) . Eligible participants had medical and vaccination records for at least four years ( since July , 2006 ) , including 578 HCP who received 2010 - 11 trivalent inactivated influenza vaccine [ IIV3 , containing A 
    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: 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 Although current guidelines target hospital employees who contact high-risk patients as a high priority for influenza immunization , there are few data to support or refute this recommendation . Therefore , the authors enrolled 179 hospital employees in a r and omized double-blind  placebo-controlled  clinical trial during the 1985–1986 influenza season .  Influenza immunization was performed without serious adverse reactions and there was no increase in absenteeism attributable to the vaccination . Among those who developed clinical influenza , there was a trend toward fewer days of illness in the vaccinated group compared with the placebo group ( 6.0 vs. 8.0 , p=0.07 ) . There were no statistically significant differences between subjects receiving influenza vaccine and those receiving the placebo when comparing incidences of influenza-like illness , severities of illness , and sick absenteeism .  Influenza immunization of hospital employees was performed at minimal cost and risk but provided little benefit , most likely because of an unexpected drift of the prevalent influenza strain away from the vaccine type BACKGROUND Successful treatment of influenza depends on an accurate diagnosis of the illness and prompt intervention . However , there is a lack of data comparing clinical diagnosis vs laboratory diagnostic techniques . OBJECTIVE To compare the clinical diagnosis of community cases of influenza with various laboratory diagnostic techniques including multiplex , reverse transcription polymerase chain reaction . METHODS Clinical diagnosis , viral isolation , hemagglutinin inhibition serology , and multiplex , reverse transcription polymerase chain reaction were used to diagnose influenza in patients enrolled in international phase 3 studies design ed to investigate the efficacy and safety of an anti-influenza drug ( inhaled zanamivir ) .  Patients clinical ly diagnosed with influenza were enrolled at centers across North America and Europe . RESULTS A total of 791 ( 77 % ) of 1033 patients with laboratory results from all 3 methods were confirmed positive for influenza by 1 or more test results . For 692 patients ( 67 % ) , the results of all 3 tests agreed . Total symptom scores at baseline showed a significant association toward greater severity of symptoms with an increasing number of positive test results ( P<.001 ) . An increasing number of positive test results also showed a significant correlation with a longer time to alleviation of symptoms of influenza in the placebo group ( P = .001 ) . CONCLUSIONS During a time when influenza was known to be circulating and clinical diagnostic criteria were applied , diagnosis of influenza in these trials was accurate in approximately 77 % of adults on clinical grounds alone . This highlights the need for primary care physicians to be alerted to circulating influenza and to be aware that presentation with cough and fever provide the most predictive symptoms BACKGROUND In healthy adults  influenza immunization reduces absenteeism caused by respiratory infections , but data on its efficacy among health care workers are scarce . OBJECTIVE To determine the effect of the conventional inactivated influenza A vaccine on reducing absenteeism related to respiratory infections among pediatric health care providers . STUDY DESIGN A r and omized , placebo-controlled , double blind study on vaccine efficacy was conducted in two pediatric hospitals during the winter season 1996 to 1997 . The primary endpoint was days of work lost from the hospital because of respiratory infections . The documentation of absenteeism was based on personal sickness logs . RESULTS Of the 547 r and omized vaccinees 427 ( 78 % ) persons completed the 4-month follow-up and returned the sickness logs . Immunization failed to reduce episodes of respiratory infections ( 1.8 episodes/ study period among vaccinees vs. 2.0 among controls ) . Similarly the vaccine failed to affect the total number of days the vaccinees suffered from respiratory infections ( 13.5 days vs. 14.6 days , respectively ) . However , days of work lost because of respiratory infections ( 1.0 days vs. 1.4 days , respectively , P = 0.02 ) and especially total numbers of days the study persons felt themselves unable to work when either on or off duty ( 2.5 days vs. 3.5 days , P 0.02 ) were significantly decreased . CONCLUSION Influenza vaccination reduced absenteeism related to respiratory infections by 28 % . We therefore believe that routine annual influenza immunizations should be recommended to health care providers working in pediatric setting INTRODUCTION Influenza vaccine has been shown to be highly effective in temperate regions with well-defined seasonal influenza . Healthcare workers ( HCWs ) are advised to receive regular influenza vaccination to protect themselves and their patients . However , there are limited data on the efficacy of influenza vaccine in HCWs in the tropics . MATERIAL S AND METHODS In this observational , investigator blinded cohort study , bi-monthly question naires recording influenza-like illness ( ILI ) episodes and medical leave were administered to 541 HCWs at the Singapore National University Hospital and KK Women 's and Children 's Hospital from 2004 to 2005 .  ILI was defined according to a st and ard symptom score . RESULTS Baseline characteristics were comparable in both the vaccinated and non-vaccinated groups . Overall , the relative risk of self-reported ILI in vaccinated HCWs was 1.13 [ 95 % confidence interval ( CI ) , 0.98 - 1.13 ; P=0.107 ] ; medical leave taken was lower in the vaccinated group [ mean 0.26+/-0.6 days per visit , compared with 0.30+/-0.5 days in the non-vaccinated group ( P=0.40 ) ] . Because of the reported Northern Hemisphere 2003/04 vaccine mismatch , we stratified the cohort and determined that the group which received a matched vaccine had a relative risk of ILI of 0.49 ( 95 % CI , 0.37 - 0.66 ; P<0.001 ) , achieving a vaccine efficacy of 51 % . Mean medical leave decreased significantly in HCWs who received the matched vaccine , compared with those who did not receive vaccination ( 0.13+/-0.3 vs 0.30+/-0.5 ; P<0.001 ) and with HCWs vaccinated with mismatched strains ( 0.13+/-0.3 vs 0.39+/-0.9 ; P=0.01 ) . CONCLUSIONS A well-matched influenza vaccine is effective in preventing ILI and reducing sickness absence in healthcare workers in tropical setting s. Efforts need to be made to increase influenza vaccination rates and to improve the currently available vaccines Background Four cluster r and omized controlled trials ( c RCTs ) conducted in long-term care facilities ( LTCFs ) have reported reductions in patient risk through increased healthcare worker ( HCW ) influenza vaccination . This evidence has led to expansive policies of enforcement that include all staff of acute care hospitals and other healthcare setting s beyond LTCFs . We critique and quantify the c RCT evidence for indirect patient benefit underpinning policies of m and atory HCW influenza vaccination . Methods Plausibility of the four c RCT findings attributing indirect patient benefits to HCW influenza vaccination was assessed by comparing percentage reductions in patient risk reported by the c RCTs to predicted values . Plausibly predicted values were derived according to the basic mathematical principle of dilution , taking into account HCW influenza vaccine coverage and the specificity of patient outcomes for influenza . Accordingly , predicted values were calculated as a function of relevant compound probabilities including vaccine efficacy ( ranging 40–60 % in HCWs and favourably assuming the same indirect protection conferred through them to patients ) × change in proportionate HCW influenza vaccine coverage ( as reported by each c RCT ) × percentage of a given patient outcome ( e.g. influenza-like illness ( ILI ) or all-cause mortality ) plausibly due to influenza virus . The number needed to vaccinate ( NNV ) for HCWs to indirectly prevent patient death was recalibrated based on real patient data of hospital-acquired influenza , with adjustment for potential under-detection ( 5.2-fold ) , and using favourable assumptions of HCW-attributable risk ( ranging 60–80 % ) . Results In attributing patient benefit to increased HCW influenza vaccine coverage , each c RCT was found to violate the basic mathematical principle of dilution by reporting greater percentage reductions with less influenza-specific patient outcomes ( i.e. , all-cause mortality > ILI > laboratory-confirmed influenza ) and /or patient mortality reductions exceeding even favourably-derived predicted values by at least 6- to 15-fold . If extrapolated to all LTCF and hospital staff in the United States , the prior c RCT -cl aim ed NNV of 8 would implausibly mean > 200,000 and > 675,000 patient deaths , respectively , could be prevented annually by HCW influenza vaccination , inconceivably exceeding total US population mortality estimates due to seasonal influenza each year , or during the 1918 p and emic , respectively . More realistic recalibration based on actual patient data instead shows that at least 6000 to 32,000 hospital workers would need to be vaccinated before a single patient death could potentially be averted . Conclusions The four c RCTs underpinning policies of enforced HCW influenza vaccination attribute implausibly large reductions in patient risk to HCW vaccination , casting serious doubts on their validity . The impression that unvaccinated HCWs place their patients at great influenza peril is exaggerated . Instead , the HCW-attributable risk and vaccine-preventable fraction both remain unknown and the NNV to achieve patient benefit still requires better underst and ing . Although current scientific data are inadequate to support the ethical implementation of enforced HCW influenza vaccination , they do not refute approaches to support voluntary vaccination or other more broadly protective practice s , such as staying home or masking when acutely ill BACKGROUND Recently , lower estimates of influenza vaccine effectiveness ( VE ) against A(H3N2 ) virus illness among those vaccinated during the previous season or multiple seasons have been reported ; however , it is unclear whether these effects are due to differences in immunogenicity . METHODS We performed hemagglutination inhibition antibody ( HI ) assays on serum collected at preseason , ∼ 30 days post-vaccination , and postseason from a prospect i ve cohort of healthcare personnel ( HCP ) . Eligible participants had medical and vaccination records for at least four years ( since July , 2006 ) , including 578 HCP who received 2010 - 11 trivalent inactivated influenza vaccine [ IIV3 , containing A 
    Output:
    