Influenza Vaccination of Health Care Personnel Working with Older Patients

Background: Health care personnel influenza rates are unknown, but may be similar to the general public and they may transmit influenza to patients. Objectives: To identify studies of vaccinating personnel and the incidence of influenza, its complications, and influenza-like illness in patients 60 years and older in long-term care facilities. Search Strategy: We searched CENTRAL (The Cochrane Library 2009, issue 3), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, Medline (1966 to 2009), EMBASE (1974 to 2009), and Biological Abstracts and Science Citation Index-Expanded. Selection Criteria: Randomized controlled trials (RCTs) and non-RCTs of influenza vaccination of personnel caring for patients 60 years and older in long-term care facilities and the incidence of laboratory-proven influenza, its complications, or influenza-like illness. Data Collection and Analysis: Two authors independently extracted data and assessed risk of bias. Main Results: We identified four cluster-RCTs (C-RCTs; n = 7,558) and one cohort (n = 12,742) of influenza vaccination for personnel caring for patients 60 years and older in long-term care facilities. Pooled data from three C-RCTs showed no effect on specific outcomes: laboratory-proven influenza, pneumonia, or deaths from pneumonia. For nonspecific outcomes, pooled data from three C-RCTs showed personnel vaccination reduced influenza-like illness; data from one C-RCT showed that personnel vaccination reduced primary care consultations for influenza-like illness; and pooled data from three C-RCTs showed reduced all-cause mortality in patients 60 years and older. Authors' Conclusions: No effect was shown for specific outcomes: laboratory-proven influenza, pneumonia, and death from pneumonia. An effect was shown for the nonspecific outcomes of influenza-like illness, primary care consultations for influenza-like illness, and all-cause mortality in patients 60 years and older. These nonspecific outcomes are difficult to interpret because influenza-like illness includes many pathogens, and winter influenza contributes less than 10 percent to all-cause mortality in patients 60 years and older. The key interest is preventing laboratory-proven influenza in patients 60 years and older, pneumonia, and deaths from pneumonia, and we cannot draw such conclusions. The identified studies are at high risk of bias. Some health care personnel remain unvaccinated because they do not perceive risk, doubt vaccine effectiveness, and are concerned about adverse effects. This review did not find information on co-interventions with personnel vaccination: hand washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding admissions, antivirals, and asking personnel with influenza-like illness not to work. We conclude there is no evidence that vaccinating personnel prevents influenza in older residents in long-term care facilities. High-quality RCTs are required to avoid risks of bias in methodology and conduct, and to test these interventions in combination.