Influenza vaccination for healthcare workers who work with the elderly

Influenza vaccination for healthcare workers who work with the elderly

Thomas RE, Jefferson T, Lasserson TJ

Summary
Influenza vaccination for healthcare workers who work with the elderly

There are no accurate data on rates of laboratory-proven influenza in healthcare workers.

The three studies in the first publication of this review and the two new studies we identified in this update are all at high risk of bias.

The studies found that vaccinating healthcare workers who look after the elderly in long-term care facilities did not show any effect on the specific outcomes of interest, namely laboratory-proven influenza, pneumonia or deaths from pneumonia. An effect was shown for outcomes with a non-specific relationship to influenza, namely influenza-like illness (which includes many other viruses and bacteria than influenza), GP consultations for influenza-like illness, hospital admissions and the overall mortality of the elderly (winter influenza is responsible for less than 10% of the deaths of individuals over 60 and overall mortality thus reflects many other causes).

Healthcare workers have lower rates of influenza vaccination than the elderly and surveys show that healthcare workers who do not get vaccinated do not perceive themselves at risk, doubt the efficacy of influenza vaccine, have concerns about side effects, and some do not perceive their patients to be at risk. This review did not find information on other interventions that can be used in conjunction with vaccinating healthcare workers, for example hand washing, face masks, early detection of laboratory-proven influenza in individuals with influenza-like illness by using nasal swabs, quarantine of floors and entire long-term care facilities during outbreaks, avoiding new admissions, prompt use of anti-virals, and asking healthcare workers with an influenza-like illness not to present for work.

We conclude that there is no evidence that only vaccinating healthcare workers prevents laboratory-proven influenza, pneumonia, and death from pneumonia in elderly residents in long-term care facilities. Other interventions such as hand washing, masks, early detection of influenza with nasal swabs, anti-virals, quarantine, restricting visitors and asking healthcare workers with an influenza-like illness not to attend work might protect individuals over 60 in long-term care facilities and high quality randomised controlled trials testing combinations of these interventions are needed.

Background
Healthcare workers’ (HCWs) 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 HCWs and the incidence of influenza, its complications and influenza-like illness (ILI) in individuals ≥ 60 in long-term care facilities (LTCFs).

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
Randomised controlled trials (RCTs) and non-RCTs of influenza vaccination of HCWs caring for individuals ≥ 60 in LTCFs and the incidence of laboratory-proven influenza, its complications or ILI.

Data collection and analysis
Two authors independently extracted data and assessed risk of bias.

Main results
We identified four cluster-RCTs (C-RCTs) (n = 7558) and one cohort (n = 12742) of influenza vaccination for HCWs caring for individuals ≥ 60 in LTCFs. Pooled data from three C-RCTs showed no effect on specific outcomes: laboratory-proven influenza, pneumonia or deaths from pneumonia. For non-specific outcomes pooled data from three C-RCTs showed HCW vaccination reduced ILI; data from one C-RCT that HCW vaccination reduced GP consultations for ILI; and pooled data from three C-RCTs showed reduced all-cause mortality in individuals ≥ 60.

Authors’ conclusions
No effect was shown for specific outcomes: laboratory-proven influenza, pneumonia and death from pneumonia. An effect was shown for the non-specific outcomes of ILI, GP consultations for ILI and all-cause mortality in individuals ≥ 60. These non-specific outcomes are difficult to interpret because ILI includes many pathogens, and winter influenza contributes < 10% to all-cause mortality in individuals ≥ 60. The key interest is preventing laboratory-proven influenza in individuals ≥ 60, pneumonia and deaths from pneumonia, and we cannot draw such conclusions.

The identified studies are at high risk of bias.

Some HCWs remain unvaccinated because they do not perceive risk, doubt vaccine efficacy and are concerned about side effects. This review did not find information on co-interventions with HCW vaccination: hand washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding admissions, anti-virals, and asking HCWs with ILI not to work. We conclude there is no evidence that vaccinating HCWs prevents influenza in elderly residents in LTCFs. High quality RCTs are required to avoid risks of bias in methodology and conduct, and to test these interventions in combination.

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This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2010 Issue 3, Copyright © 2010 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).

This record should be cited as: Thomas RE, Jefferson T, Lasserson TJ. Influenza vaccination for healthcare workers who work with the elderly. Cochrane Database of Systematic Reviews 2010, Issue 2. Art. No.: CD005187. DOI: 10.1002/14651858.CD005187.pub3.


Dr. Darryl Roundy

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