Effect of Influenza Vaccination of Healthcare Personnel on Morbidity and Mortality Among Patients: Systematic Review and Grading of Evidence

• Published in: Clinical infectious diseases Vol. 58; no. 1; pp. 50 - 57
• Main Authors: Ahmed, Faruque, Lindley, Megan C., Allred, Norma, Weinbaum, Cindy M., Grohskopf, Lisa
• Format: Journal Article
• Language: English
• Published: Oxford OXFORD UNIVERSITY PRESS 01.01.2014; Oxford University Press
• Subjects: ARTICLES AND COMMENTARIES; Assumption of risk; Biological and medical sciences; Control groups; Cross Infection - epidemiology; Cross Infection - mortality; Cross Infection - prevention & control; Empirical evidence; Health care; Health care industry; Health outcomes; Health Personnel; Hospitalization; Human viral diseases; Humans; Immunization; Infectious diseases; Influenza; Influenza vaccines; Influenza Vaccines - administration & dosage; Influenza, Human - epidemiology; Influenza, Human - mortality; Influenza, Human - prevention & control; Medical personnel; Medical sciences; Morbidity; Mortality; Mortality rates; Observational studies; Randomized controlled trials; Risk assessment; Survival Analysis; Vaccination - methods; Viral diseases; Viral diseases of the respiratory system and ent viral diseases; influenza vaccines; quality of healthcare; evidence-based medicine; decision making; health personnel; Infection; Prevention; Human; Immunoprophylaxis; Prognosis; Viral disease; Influenza; Mortality; Vaccination; Health care staff; Morbidity; Bibliographic review
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/cid/cit580

Background. Influenza vaccination of healthcare personnel (HCP) is recommended in >40 countries. However, there is controversy surrounding the evidence that HCP vaccination reduces morbidity and mortality among patients. Key factors for developing evidence-based recommendations include quality of evidence, balance of benefits and harms, and values and preferences. Methods. We conducted a systematic review of randomized trials, cohort studies, and case-control studies published through June 2012 to evaluate the effect of HCP influenza vaccination on mortality, hospitalization, and influenza cases in patients of healthcare facilities. We pooled trial results using meta-analysis and assessed evidence quality using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results. We identified 4 cluster randomized trials and 4 observational studies conducted in long-term care or hospital settings. Pooled risk ratios across trials for all-cause mortality and influenza-like illness were 0.71 (95% confidence interval [CI], .59–.85) and 0.58 (95% CI, .46–.73), respectively; pooled estimates for all-cause hospitalization and laboratory-confirmed influenza were not statistically significant. The cohort and case-control studies indicated significant protective associations for influenza-like illness and laboratory-confirmed influenza. No studies reported harms to patients. Using GRADE, the quality of the evidence for the effect of HCP vaccination on mortality and influenza cases in patients was moderate and low, respectively. The evidence quality for the effect of HCP vaccination on patient hospitalization was low. The overall evidence quality was moderate. Conclusions. The quality of evidence is higher for mortality than for other outcomes. HCP influenza vaccination can enhance patient safety.